Debt (Senior Secured Credit Facilities) (Details)	9 Months Ended
	Sep. 30, 2015 USD ($)	May. 12, 2015 USD ($)
Domestic Subsidiary [Member]
Line of Credit Facility [Line Items]
Collateral as percentage of common stock	100.00%
Foreign Subsidiary [Member]
Line of Credit Facility [Line Items]
Collateral as percentage of common stock	65.00%
The Term Loan Facility [Member]
Line of Credit Facility [Line Items]
Debt instrument term	7 years
Line of credit facility, maximum borrowing capacity		$ 1,500,000,000
Periodic payment, percentage of face amount	1.00%
Unamortized discount	$ 7,000,000	7,000,000
Stated percentage rate, minimum	3.75%
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt instrument term	5 years
Line of credit facility, maximum borrowing capacity		$ 1,000,000,000
Letters of credit outstanding	$ 129,000,000
Commitment fee percentage	0.30%
Leverage ratio maximum	3.00
Revolving Credit Facility [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Unused capacity commitment fee percentage	0.20%
Revolving Credit Facility [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Unused capacity commitment fee percentage	0.35%
Revolving Credit Facility [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Variable rate	1.00%
Revolving Credit Facility [Member] | Base Rate [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Variable rate	0.50%
Revolving Credit Facility [Member] | Base Rate [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Variable rate	1.25%
Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Variable rate	2.00%
Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Variable rate	1.50%
Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Variable rate	2.25%