Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Net income	$ 5,418	$ 5,346	$ 5,388
Net income attributable to noncontrolling interests	49	45	50
Preferred stock dividends	236	236	236
Preferred stock discount accretion and redemptions	4	4	26
Net income attributable to common shares	5,129	5,061	5,076
Less: Dividends and undistributed earnings allocated to participating securities	21	21	23
Net income attributable to basic common shareholders	5,108	5,040	5,053
Less: Impact of BlackRock earnings per share dilution	10	9	16
Net income attributable to diluted common shareholders	$ 5,098	$ 5,031	$ 5,037
Weighted Average Number of Shares Outstanding, Basic (shares)	447	467	481
Basic earnings per common share (dollars per share)	$ 11.43	$ 10.79	$ 10.49
Dilutive potential common shares	1	3	5
Weighted Average Number of Shares Outstanding, Diluted (shares)	448	470	486
Diluted earnings per common share (dollars per share)	$ 11.39	$ 10.71	$ 10.36