Second-quarter earnings for our favorite pipeline companies kicked off with Kinder Morgan (KMI -0.21%) and Kinder Morgan Energy Partners (NYSE: KMP) reporting yesterday after the market close. Revenue for KMP popped more than $1 billion year over year, to $3.02 billion. The growth came largely at the hands of the partnership's two most recent acquisitions, but there is plenty more for investors to consider beyond that, so let's break down the earnings of the individual segments.

Segment review
For a partnership of its size, Kinder Morgan remains fairly diverse. This is how its earnings look on a per-segment basis, before debt, depreciation, and amortization.

With the exception of that small slice that is Kinder Morgan Canada, every segment is outperforming its year-ago results. Now, let's take a closer look at each business.

  • Natural gas pipelines was far and away the best performer, based largely on two full months of earnings from the Copano acquisition, and the continued drop-downs from the El Paso acquisition. Earnings more than doubled from $238 million last year, to $566 million this year. One thing to note here, is that while volumes increased on the Texas intrastate lines, there was a substantial decrease on the lines supplying power generation customers. This is part of a national trend that Kinder Morgan avoided in the first quarter, but succumbed to this quarter. Management remains bullish on natural gas.
  • The CO2 business grew 1% in the first quarter, but was up 10% year over year in the second, with earnings of $351 million. This segment carries a fair bit of commodity risk, which both helped and hurt this quarter. Oil prices were up, which is good, but natural gas liquids prices were down 11% over last year, which is obviously bad. Oil production was also up, however, and that combined with higher prices drove growth in this segment. The demand for CO2 from Permian Basin producers continues to grow and Kinder Morgan is exploring some expansion opportunities, which means the future outlook for this segment remains bright, despite the prolonged depression of natural gas liquids prices.
  • Products pipelines earnings grew 8% year over year, to $179 million. Management attributed growth in its segment to its transmix operation, which posted higher volumes and higher margins. Remember, transmix is the business that generates renewable identification numbers which Kinder Morgan can then sell on the secondary market. Outside of transmix, natural gas liquids volumes, biofuel volumes, and refined products volumes were all up.
  • Terminals earnings grew 5% year over year to $191 million. It should be noted that as the Copano and El Paso acquisitions make the earnings headlines, this segment had mostly organic growth, driven by increasing coal export volumes, and new or restructured contracts sporting higher rates. Domestic coal volumes continue to drop, however, as do steel volumes.
  • Kinder Morgan Canada was the one underperforming segment in the second quarter, earning $50 million in 2013, compared to $52 million last year. This is solely because of the sale of the Express-Platte system, which management has said will be accretive when all is said and done, though this segment will continue to post lower numbers year over year. As far as a future outlook goes, Canada's National Energy Board has approved the commercial terms of Kinder Morgan's Trans Mountain expansion. The partnership will submit its facilities application for building and operation later this year. If all goes according to plan, the expansion is slated to be in service by 2017.

Clearly, the partnership's two most recent acquisitions are really making an impact, especially in the natural gas segment. However, the Kinder Morgan's diversity remains its core strength.

Foolish takeaway
The strong quarterly performance means that Kinder Morgan is able to remain on track with its dividend and distribution growth. Both KMI and KMP increased their quarterly payout to $0.40 and $1.32, respectively. Both entities are expected to hit their annualized targets of $1.60 and $5.33 per unit.