Given how unpredictable the stock market is, investors in their golden years need to look for safe companies that can offer good growth in the long term while generating reliable income as of dividends. At the same time, finding such a company is never easy.

So we've tried to make it a little easy for you by asking our three Motley Fool contributors to suggest stock ideas that a retiree can consider buying today. Read on to know why Waste Management (NYSE:WM), Chevron Corporation (NYSE:CVX), and Potash Corp. (NYSE:POT) made the list.

Joe Tenebruso (Waste Management): When I think of stocks for retirees, I think of two things: safety and cash flow. Safety, because dividend income comprises an important part of many retirees' income streams, the loss of which could be financially devastating. And cash flow, because it's that cash that allows companies to pay out dividends to their shareholders.

Waste Management is an excellent combination of safety and cash flow. That's because unless people stop producing garbage, Waste Management's trash collection and recycling services will always be in demand.

Image source: Waste Management

What's more, thanks to regulatory and political hurdles, it's difficult to build new landfills in many areas of the U.S. That makes Waste Management's existing nationwide network of landfills, collection facilities, and recycling centers a valuable collection of nearly replaceable assets, which combine to form a competitive moat that protects the garbage king's impressive cash generation

There's also a near-term catalyst that could help drive Waste Management's shares higher; U.S. household formation is finally picking up and new home construction is likely to follow. More construction means more trash for Waste Management to collect -- and more cash for its shareholders.

Bob Ciura (Chevron Corporation): Despite everything going on in the oil and gas markets, I believe Chevron Corporation is an attractive stock pick for a retirees' portfolio. When I evaluate stocks for retirees, first and foremost to me is a secure dividend. Chevron's stock price is plunging—down 25% just since the start of the year—but this has presented a unique dividend opportunity.

Thanks to its declining stock price, Chevron's dividend yield now exceeds 5%, which is a very rare event for this stock. In fact, Chevron's dividend yield didn't eclipse 5% even during the depths of the 2008-2009 market downturn. Chevron's current dividend yield represents a 10-year high.

Of course, the biggest reason for this is that Chevron's profits are in free-fall due to the oil crash. Earnings collapsed 90% last quarter, year over year.

But Chevron is taking the necessary steps to protect its dividend. The company suspended stock buybacks this year, which freed up $5 billion. In addition, Chevron is aggressively selling assets deemed non-critical to the future. The company realized approximately $4 billion in divestments over the first four months of this year, and is on track to raise as much as $15 billion over its stated 48-month divestment program.

Thanks to these actions, Chevron expects the dividend to be fully covered by free cash flow by 2017. Chevron should be able to at least maintain its dividend until then. It is a Dividend Aristocrat, having raised dividends for 27 years in a row. The company understands how seriously investors take the dividend, and I believe it will maintain its dividend through the rough patch. For that reason, I believe Chevron's 5% dividend yield should be attractive for retirees. 

Neha Chamaria (Potash Corp.): When selecting stocks, I believe retirees should look for companies that have a strong economic moat in businesses with good growth prospects, and offer reliable dividends. Potash Corp. (NYSE:POT) fits the bill.

One of the world's biggest challenges today is growing enough food for a rapidly rising population. Fertilizers play an important role in addressing the concern by providing essential nutrients to soil that boost crop productivity. PotashCorp is the world's largest fertilizer company that manufacturers all three essential nutrients -- potash, nitrogen, and phosphate.

While that explains why PotashCorp's business has immense growth potential, the company currently yields 5.5% in dividends – the best in the industry. PotashCorp's dividend has grown more than 11 times since 2007, and it has returned $11.1 billion to shareholders between 2005 and 2014 while investing $13.6 billion in capital projects over the period.

Best of all, with its multi-billion dollar expansion program in its last leg, PotashCorp's capital expenditure should decline substantially in coming years, thereby freeing up more cash to return to shareholders. With the stock currently trading near its 52-week low, I think PotashCorp offers the advantages of both value and dividend investing – an excellent combination for a retiree.