Earnings per Share (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Earnings Per Share Basic and Diluted [Line Items]
Net income	$ 1,038,000,000	[1]	$ 1,028,000,000	[1]	$ 3,150,000,000	[1]	$ 3,138,000,000	[1]
Net income (loss) attributable to noncontrolling interests	1,000,000	[1]	2,000,000	[1]	2,000,000	[1]	(2,000,000)	[1]
Preferred stock dividends and discount accretion and redemptions	71,000,000		71,000,000		189,000,000		199,000,000
Net income attributable to common shareholders	966,000,000		955,000,000		2,959,000,000		2,941,000,000
Dividends and undistributed earnings allocated to nonvested restricted shares	3,000,000		4,000,000		9,000,000		13,000,000
Net income attributable to basic common shares	963,000,000		951,000,000		2,950,000,000		2,928,000,000
Less: Impact of BlackRock earnings per share dilution	4,000,000		4,000,000		13,000,000		13,000,000
Net income attributable to diluted common shares	$ 959,000,000		$ 947,000,000		$ 2,937,000,000		$ 2,915,000,000
Basic weighted-average common shares outstanding	529		529		531		528
Basic earnings per common share (b)	$ 1.82		$ 1.8		$ 5.55		$ 5.55
Dilutive potential common shares (c) (d)	8		5		8		3
Diluted weighted-average common shares outstanding	537		534		539		531
Diluted earnings per common share (b)	$ 1.79		$ 1.77		$ 5.45		$ 5.49
Stock Option [Member]
Earnings Per Share Basic and Diluted [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	0		1		0		1

[1] Amounts for 2013 periods have been updated to reflect the first quarter 2014 adoption of Accounting Standards Update (ASU) 2014-01 related to investments in low income housing tax credits.