Capital Stock (Details 2) (USD $)	1 Months Ended				1 Months Ended			1 Months Ended
	Feb. 28, 2011	Dec. 31, 2011	Jul. 01, 2011	Dec. 31, 2010	Jul. 31, 2011 NHP	Dec. 31, 2011 NHP	Jul. 01, 2011 NHP	Nov. 30, 2011 ASLG	May 31, 2011 ASLG	May 12, 2011 ASLG
Business acquisition
Number of shares reserved for issuance in connection with equity awards and other convertible or exchangeable securities						2,253,366	2,253,366
Common stock share value issued related to acquisition							$ 5,400,000,000			$ 1,380,000,000
Closing price of Common stock							$ 53.74			$ 55.33
Number of common stock issued related to acquisition					99,849,106				24,958,543
Number of shares reduced for working capital adjustment with purchase agreement								83,441
Number of shares of common stock issued and sold in an underwritten public offering	5,563,000
Aggregate proceeds from the sale of common stock in an underwritten public offering pursuant	$ 300,000,000
Capital stock authorized (in shares)		610,000,000	610,000,000
Common stock, shares authorized		600,000,000	600,000,000	300,000,000
Common stock, par value (in dollars per share)		$ 0.25	$ 0.25	$ 0.25
Preferred stock, shares authorized		10,000,000	10,000,000	10,000,000
Preferred stock, par value (in dollars per share)		$ 1.00	$ 1.00	$ 1.00