Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share Basic and Diluted [Line Items]
Net income	$ 943	$ 1,004
Net income (loss) attributable to noncontrolling interests	19	1
Preferred stock dividends and discount accretion and redemptions	65	70
Net income attributable to common shares	859	933
Dividends and undistributed earnings allocated to participating securities	6	2
Net income attributable to basic common shares	853	931
Less: Impact of BlackRock earnings per share dilution	3	5
Net income attributable to diluted common shares	$ 850	$ 926
Basic weighted-average common shares outstanding	501	521
Basic earnings per common share	$ 1.7	$ 1.79
Dilutive potential common shares	6	8
Diluted weighted-average common shares outstanding	507	529
Diluted earnings per common share	$ 1.68	$ 1.75