Debt (Revolving Credit Facility Under The Senior Credit Agreement) (Narrative) (Details) (USD $)	6 Months Ended		0 Months Ended	3 Months Ended	6 Months Ended		0 Months Ended				6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Feb. 07, 2014 Revolving Credit Facility [Member]	Jun. 30, 2014 Revolving Credit Facility [Member]	Jun. 30, 2014 Revolving Credit Facility [Member]	Feb. 07, 2014 2014 Term Loan [Member]	Feb. 07, 2014 2014 Term Loan [Member] Eurodollar [Member]	Feb. 07, 2014 2014 Term Loan [Member] Base Rate [Member]	Jul. 01, 2014 4.875% Senior Notes [Member]	Jun. 30, 2014 4.875% Senior Notes [Member]	Jun. 30, 2014 Minimum [Member] Eurodollar [Member]	Jun. 30, 2014 Minimum [Member] Base Rate [Member]	Jun. 30, 2014 Minimum [Member] Revolving Credit Facility [Member]	Jun. 30, 2014 Maximum [Member] Eurodollar [Member]	Jun. 30, 2014 Maximum [Member] Base Rate [Member]	Jun. 30, 2014 Maximum [Member] Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity				$ 770,000,000	$ 770,000,000
Basis spread on variable interest rate							2.50%	1.50%			1.875%	0.875%		2.375%	1.375%
Line of credit facility, commitment fee													0.375%			0.50%
Borrowings on the revolving credit facility				100,000,000	275,000,000
Repayments of revolving credit facility	390,000,000	225,000,000	390,000,000		390,000,000
Line of credit facility, outstanding				100,000,000	100,000,000
Debt instrument, interest rate, stated percentage									4.875%	4.875%
Line of credit facility, remaining borrowing capacity				720,000,000	720,000,000
Debt instrument, face amount						$ 1,500,000,000