Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Net income	$ 915	$ 1,271
Net income attributable to noncontrolling interests	7	10
Preferred stock dividends	63	63
Preferred stock discount accretion and redemptions	1	1
Net income attributable to common shareholders	844	1,197
Less: Dividends and undistributed earnings allocated to participating securities	4	5
Net income attributable to basic common shares	$ 840	$ 1,192
Basic weighted-average common shares outstanding (in shares)	429	455
Basic earnings per common share (in dollars per share)	$ 1.96	$ 2.62
Less: Impact of BlackRock earnings per share dilution	$ 1	$ 3
Net income attributable to diluted common shares	$ 839	$ 1,189
Dilutive potential common shares (in shares)	1	1
Diluted weighted-average common shares outstanding (in shares)	430	456
Diluted earnings per common share (in dollars per share)	$ 1.95	$ 2.61