Earnings per Share (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share Basic and Diluted [Line Items]
Net income	$ 4,143,000,000	$ 4,207,000,000	$ 4,212,000,000
Net income (loss) attributable to noncontrolling interests	37,000,000	23,000,000	11,000,000
Preferred stock dividends and discount accretion and redemptions	225,000,000	237,000,000	249,000,000
Net income attributable to common shares	3,881,000,000	3,947,000,000	3,952,000,000
Dividends and undistributed earnings allocated to participating securities	17,000,000	11,000,000	18,000,000
Net income attributable to basic common shares	3,864,000,000	3,936,000,000	3,934,000,000
Less: Impact of BlackRock earnings per share dilution	18,000,000	18,000,000	18,000,000
Net income attributable to diluted common shares	$ 3,846,000,000	$ 3,918,000,000	$ 3,916,000,000
Basic weighted-average common shares outstanding	514,000,000	529,000,000	528,000,000
Basic earnings per common share	$ 7.52	$ 7.44	$ 7.45
Dilutive potential common shares	7,000,000	8,000,000	4,000,000
Diluted weighted-average common shares outstanding	521,000,000	537,000,000	532,000,000
Diluted earnings per common share	$ 7.39	$ 7.3	$ 7.36
Stock Option [Member]
Earnings Per Share Basic and Diluted [Line Items]
Antidilutive securities excluded from computation of earnings per share amount			1,000,000