Earnings per Common Share - Basic and Diluted EPS Calculations (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Net Income—Controlling Interests		$ 195	$ 174	$ 578	$ 459
Weighted-average common shares outstanding
Basic		701	671	692	671
Diluted		703	672	693	672
Earnings Per Share, Basic	[1]	$ 0.28	$ 0.26	$ 0.84	$ 0.68
Earnings Per Share, Diluted	[1]	$ 0.28	$ 0.26	$ 0.83	$ 0.68

[1] Quarterly earnings per share amounts are stand-alone calculations and may not be additive to full-year amounts due to rounding.