Earnings per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010
Net income from continuing operations	$ 912		$ 781		$ 1,744		$ 1,429
Net income (loss) attributable to noncontrolling interests	(1)		(9)		(6)		(14)
Dividends distributed to common shareholders	183		53		236		98
Dividends distributed to preferred shareholders	24		25		28		118
Dividends Distributed To Nonvested Restricted Shares	1				1
Preferred stock discount accretion	1		1		1		251
Undistributed net income from continuing operations	704		711		1,484		976
Undistributed net income from discontinued operations			22				45
Undistributed net income	704		733		1,484		1,021
Percentage of undistributed income allocated to common shares	99.57%		99.61%		99.62%		99.65%
Undistributed income from continuing operations allocated to common shares	701		708		1,479		972
Net income from discontinued operations attributable to common shares			22				45
Net income attributable to basic common shares	884		783		1,715		1,115
Basic weighted-average common shares outstanding	524		524		524		511
Basic earnings per common share from continuing operations	$ 1.69		$ 1.45		$ 3.27		$ 2.09
Basic earnings per common share from discontinued operations			$ 0.04				$ 0.09
Basic earnings per common share	$ 1.69		$ 1.49		$ 3.27		$ 2.18
Net income from continuing operations attributable to basic common shares	884		761		1,715		1,070
Less: BlackRock common stock equivalents	4		6		10		8
Net income from continuing operations attributable to diluted common shares	880		755		1,705		1,062
Net income attributable to diluted common shares	$ 880		$ 777		$ 1,705		$ 1,107
Dilutive potential common shares (a) (b)	3	[1],[2]	3	[1],[2]	3	[1],[2]	3	[1],[2]
Diluted weighted-average common shares outstanding	527		527		527		514
Diluted earnings per common share from continuing operations	$ 1.67		$ 1.43		$ 3.24		$ 2.06
Diluted earnings per common share from discontinued operations			$ 0.04				$ 0.09
Diluted earnings per common share	$ 1.67		$ 1.47		$ 3.24		$ 2.15
Stock Options [Member]
Antidilutive securities excluded from computation of earnings per share amount	5		11		5		12
Warrants [Member]
Antidilutive securities excluded from computation of earnings per share amount	22		22		22		22

[1] Excludes stock options considered to be anti-dilutive

[2] Excludes warrants considered to be anti-dilutive