Factory floors are often filled with products from 3M and GE, even though you may never see their names. Image source: Getty Images.

One of the best things about investing is that you can make money by doing absolutely nothing. But some stocks require constant babysitting to make sure your investment thesis hasn't changed or that a company's financials aren't going south.

If you're looking for companies you don't have to babysit, these three are a good place to start.

The "do everything" company

One of the ways to invest in stocks you don't have to babysit is by going after diversification. And there may be no company more diversified than 3M (MMM 0.86%).

3M serves nearly every major business sector, from energy to electronics to consumer goods. It's well known for products like Post-it Notes and Scotch tape, but most of its money is made by selling less high-profile items like films in the screen of your smartphone, or the braces your teenager might be wearing. This allows 3M to put most of its focus on building better technology for its business customers, rather than building a brand you'll buy knowingly.

On the financial front, 3M is about as consistent as a business gets. You can see that revenue, net income, and free cash flow have all grown steadily since 2000, and that trend goes back many decades:

MMM Net Income (TTM) Chart

MMM Net Income (TTM) data by YCharts.

The icing on the cake is that 3M has paid a dividend for 100 consecutive years, and has increased its payout to investors for 58 straight years. That's the kind of stock I want to own if I'm not interested in babysitting.

Powering the world

General Electric (GE -3.19%) may not be the first name you think of when you think of energy, but it's a huge player in the industry. It builds everything from power plants to airplane engines to lightbulbs. And the company has lessened its dependence on financial services since the financial crisis, lowering risk to the business overall. 

But what makes this a stock to own long-term is management's continual ability to evolve toward tomorrow's industrial needs. While the company has core products like lighting and turbines, GE always seems to find a new way to turn its core technologies into growth. For example, GE is one of the world's largest wind-turbine manufacturers, and is getting a lot of business from the growth of natural-gas power plants that are cleaner than coal. And it's investing in digital services that will tie energy products together in a smarter way.

GE has been able to leverage its significant technology capabilities to expand, and to grow into new markets that keep the business pulling in cash year after year. And with a management team willing to adapt to change, and a 3.1% dividend yield to fall back on, this is a stock you don't have to think about more than every few years. 

Image source: Getty Images.

The new kid on the block

The relative safety of 3M and GE as investments is rooted in their size and diversification. But another way a company can provide safe cash flows from long-term contracts that turn into dividends for investors -- and that's why 8point3 Energy Partners (CAFD) is a stock you don't have to babysit.

8point3 Energy Partners is a yieldco that owns solar-energy projects with long-term contracts to sell energy to utilities. And the revenue generated from those projects is then paid to investors in the form of a dividend, which right now stands at 5.9% annually, with 12% to 15% growth expected for at least the next two years.

The reason this is a stock you don't have to babysit is the long-term contracts these solar projects have with utilities. Unless you think utilities across the country are going to go bankrupt, this is about as safe as a dividend gets for investors.