Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Summarization of principal contractual obligations
Future minimum payments under the non-cancelable operating leases	$ 229.3		$ 229.3
Rent expense	12.6	15.7	39.9	47.2
Total purchase commitments	553.3		553.3
Accrual for estimated carrying charges or obsolete materials charges	24.2		24.2
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	92.0		92.0
Campus build out commitments	24.0		24.0
Other contractual obligations	16.1		16.1
Long-term income taxes payable	117.5		117.5		112.4
Fixed rate note due 2016
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
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
Summarization of principal contractual obligations
Long-term debt, gross	$ 400.0		$ 400.0
Long-term debt, interest rate, Stated percentage	5.95%		5.95%