Earnings per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income from continuing operations	$ 834		$ 775		$ 2,578		$ 2,204
Net income (loss) attributable to noncontrolling interests	4		2		(2)		(12)
Dividends distributed to common shareholders	183		53		419		151
Dividends distributed to preferred shareholders	4		4		32		122
Dividends distributed to nonvested restricted shares	1				2
Preferred stock discount accretion and redemptions	0		3		1		254
Undistributed net income from continuing operations	642		713		2,126		1,689
Undistributed net income from discontinued operations			328				373
Undistributed net income	642		1,041		2,126		2,062
Percentage of undistributed income allocated to common shares	99.55%		99.63%		99.60%		99.64%
Undistributed income from continuing operations allocated to common shares	639		709		2,118		1,681
Net income from discontinued operations attributable to common shares			328				373
Net income attributable to basic common shares	822		1,090		2,537		2,205
Basic weighted-average common shares outstanding	524		523		524		515
Basic earnings per common share from continuing operations	$ 1.57		$ 1.45		$ 4.84		$ 3.56
Basic earnings per common share from discontinued operations			$ 0.63				$ 0.72
Basic earnings per common share	$ 1.57		$ 2.08		$ 4.84		$ 4.28
Net income from continuing operations attributable to basic common shares	822		762		2,537		1,832
Less: BlackRock common stock equivalents	6		3		16		11
Net income from continuing operations attributable to diluted common shares	816		759		2,521		1,821
Net income attributable to diluted common shares	$ 816		$ 1,087		$ 2,521		$ 2,194
Dilutive potential common shares (a) (b)	2	[1],[2]	3	[1],[2]	2	[1],[2]	3	[1],[2]
Diluted weighted-average common shares outstanding	526		526		526		518
Diluted earnings per common share from continuing operations	$ 1.55		$ 1.45		$ 4.79		$ 3.52
Diluted earnings per common share from discontinued operations			$ 0.62				$ 0.72
Diluted earnings per common share	$ 1.55		$ 2.07		$ 4.79		$ 4.24
Stock Options [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	12		13		7		11
Warrants [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
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