Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Summarization of principal contractual obligations
Future minimum payments under the non-cancelable operating leases	$ 239.5		$ 239.5
Rent expense	13.6	15.8	27.3	31.5
Total purchase commitments	572.3		572.3
Accrual for estimated carrying charges or obsolete materials charges	27.6		27.6
Long-term debt, carrying value	999.3		999.3		999.2
Long-term debt, gross	1,000.0		1,000.0
Indemnity-related and service-related escrows	94.0		94.0
Campus build out commitments	40.8		40.8
Other contractual obligations	11.6		11.6
Long-term income taxes payable	115.7		115.7		112.4
Fixed Rate Note Due 2016 [Member]
Summarization of principal contractual obligations
Long-term debt, gross	300.0		300.0
Long-term debt, interest rate, Stated percentage	3.10%		3.10%
Fixed Rate Note Due 2021 [Member]
Summarization of principal contractual obligations
Long-term debt, gross	300.0		300.0
Long-term debt, interest rate, Stated percentage	4.60%		4.60%
Fixed Rate Note Due 2041 [Member]
Summarization of principal contractual obligations
Long-term debt, gross	$ 400.0		$ 400.0
Long-term debt, interest rate, Stated percentage	5.95%		5.95%