Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Net income	$ 1,239	$ 1,074
Net income attributable to noncontrolling interests	10	17
Preferred stock dividends	63	63
Preferred stock discount accretion and redemptions	1	21
Net Income Loss Available To Common Stockholders	1,165	973
Dividends and undistributed earnings allocated to participating securities	5	6
Net income attributable to basic common shares	$ 1,160	$ 967
Basic weighted-average common shares outstanding	473	487
Basic earnings per common share	$ 2.45	$ 1.99
Less: Impact of BlackRock earnings per share dilution	$ 2	$ 4
Net income attributable to diluted common shares	$ 1,158	$ 963
Dilutive potential common shares	3	5
Diluted weighted-average common shares outstanding	476	492
Diluted earnings per common share	$ 2.43	$ 1.96