Stockholders' Equity - Common Stock Rollforward (Detail)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Shares of common stock issued
Shares at January 1	513,300,000	509,000,000	476,000,000
Issuance of common stock			30,000,000
Exercise of stock options	1,120,000	2,000,000	1,000,000
Issuance of restricted stock	2,000,000	2,000,000	2,000,000
Shares at December 31	516,000,000	513,300,000	509,000,000
Shares of common stock held in treasury
Shares at January 1	17,100,000	16,000,000	16,000,000
Shares received for restricted stock vested and options exercised	1,000,000	1,000,000
Shares at December 31	17,600,000	17,100,000	16,000,000
Shares of common stock outstanding at December 31	498,000,000	496,000,000	493,000,000