Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share Basic and Diluted [Line Items]
Net income	$ 1,044,000,000	$ 1,052,000,000	$ 2,048,000,000	$ 2,112,000,000
Net income (loss) attributable to noncontrolling interests	4,000,000	3,000,000	5,000,000	1,000,000
Preferred stock dividends and discount accretion and redemptions	48,000,000	48,000,000	118,000,000	118,000,000
Net income attributable to common shares	992,000,000	1,001,000,000	1,925,000,000	1,993,000,000
Dividends and undistributed earnings allocated to nonvested restricted shares		3,000,000	2,000,000	6,000,000
Net income attributable to basic common shares	992,000,000	998,000,000	1,923,000,000	1,987,000,000
Less: Impact of BlackRock earnings per share dilution	5,000,000	3,000,000	10,000,000	9,000,000
Net income attributable to diluted common shares	$ 987,000,000	$ 995,000,000	$ 1,913,000,000	$ 1,978,000,000
Basic weighted-average common shares outstanding	517	532	519	532
Basic earnings per common share (a)	$ 1.92	$ 1.88	$ 3.71	$ 3.73
Dilutive potential common shares (b) (c)	8	7	8	7
Diluted weighted-average common shares outstanding	525	539	527	539
Diluted earnings per common share (a)	$ 1.88	$ 1.85	$ 3.63	$ 3.67
Stock Option [Member]
Earnings Per Share Basic and Diluted [Line Items]
Antidilutive securities excluded from computation of earnings per share amount		1		1