Capital Stock (Details 2) (USD $)				1 Months Ended		0 Months Ended			1 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Jul. 02, 2011	Jun. 30, 2012 Common Stock Par Value	Feb. 28, 2011 Common Stock Par Value	Jul. 02, 2011 NHP	Nov. 02, 2011 ASLG	May 12, 2011 ASLG	May 31, 2011 ASLG
Business acquisition
Number of common stock issued related to acquisition						99,849,106		24,958,543	24,958,543
Common stock share value issued related to acquisition						$ 5,400,000,000		$ 1,380,000,000
Number of shares reserved for issuance in connection with equity awards and other convertible or exchangeable securities						2,253,366
Closing price of Common stock						$ 53.74		$ 55.33
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				5,980,000	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
Common stock, shares authorized	600,000,000	600,000,000	600,000,000
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	$ 1	$ 1.00