Earnings per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 925		$ 834		$ 2,282		$ 2,578
Net income (loss) attributable to noncontrolling interests	(14)		4		(13)		(2)
Preferred Stock Dividends and Other Adjustments	63		4		127		33
Dividends and undistributed earnings allocated to nonvested restricted shares	5		4		10		10
Net income attributable to basic common shares	871		822		2,158		2,537
Basic weighted-average common shares outstanding	526		524		526		524
Basic earnings per common share (a)	$ 1.66	[1]	$ 1.57	[1]	$ 4.10	[1]	$ 4.84	[1]
Less: BlackRock common stock equivalents	3		6		10		16
Net income attributable to diluted common shares	$ 868		$ 816		$ 2,148		$ 2,521
Dilutive potential common shares (b) (c)	3	[2],[3]	2	[2],[3]	3	[2],[3]	2	[2],[3]
Diluted weighted-average common shares outstanding	529		526		529		526
Diluted earnings per common share	$ 1.64	[1]	$ 1.55	[1]	$ 4.06	[1]	$ 4.79	[1]
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	5		12		5		7
Warrant [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	17		22		17		22

[1] Basic and diluted earnings per share under the two-class method are determined on net income reported on the income statement less earnings allocated to nonvested restricted shares (participating securities).

[2] Excludes number of stock options considered to be anti-dilutive of 5 million and 12 million for the three months ended September 30, 2012 and September 30, 2011, respectively, and 5 million and 7 million for the nine months ended September 30, 2012 and September 30, 2011, respectively.

[3] Excludes number of warrants considered to be anti-dilutive of 17 million and 22 million for the three months ended September 30, 2012 and September 30, 2011, respectively, and 17 million and 22 million for the nine months ended September 30, 2012 and September 30, 2011, respectively.