Long-Term Debt (Schedule Of Long-Term Debt) (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2016	Dec. 31, 2015
Long-term debt [Line Items]
Less current portion		$ (64)	$ (54)
Total long-term debt		2,721	2,698
Vehicle Capital Leases [Member]
Long-term debt [Line Items]
Vehicle capital leases	[1]	$ 83	47
Borrowing margin (as a percent)		2.45%
Variable rate basis		one-month LIBOR
Senior Secured Term Loan Facility Maturing In 2021 [Member]
Long-term debt [Line Items]
Long-term debt	[2],[3]	$ 2,323	2,336
Unamortized debt issuance costs		18	21
Unamortized original issue discount		14	17
Revolving Credit Facility Maturing In 2019 [Member]
Long-term debt [Line Items]
Long-term debt	[3]
7.10% Notes Maturing In 2018 [Member]
Long-term debt [Line Items]
Long-term debt	[4]	$ 77	75
Interest rate (as a percent)		7.10%
7.45% Notes Maturing In 2027 [Member]
Long-term debt [Line Items]
Long-term debt	[4]	$ 166	164
Interest rate (as a percent)		7.45%
7.25% Notes Maturing In 2038 [Member]
Long-term debt [Line Items]
Long-term debt	[4]	$ 65	65
Interest rate (as a percent)		7.25%
7.10% Notes, 7.45% Notes, 7.25% Notes Collectively [Member]
Long-term debt [Line Items]
Unamortized fair value adjustments related to purchase accounting		$ 49	53
Other [Member]
Long-term debt [Line Items]
Long-term debt		$ 70	$ 65
Minimum [Member] | Senior Secured Term Loan Facility Maturing In 2021 [Member] | LIBOR [Member]
Long-term debt [Line Items]
Interest rate (as a percent)		1.00%
Borrowing margin (as a percent)		3.25%
Minimum [Member] | Senior Secured Term Loan Facility Maturing In 2021 [Member] | Alternative Base Rate [Member]
Long-term debt [Line Items]
Interest rate (as a percent)		2.00%
Borrowing margin (as a percent)		2.25%

[1] The Company has entered into a fleet management services agreement (the "Fleet Agreement") which, among other things, allows the Company to obtain fleet vehicles through a leasing program. All leases under the Fleet Agreement are capital leases for accounting purposes. The lease rental payments include an interest component calculated using a variable rate based on one-month LIBOR plus other contractual adjustments and a borrowing margin totaling 2.45 percent.

[2] As of September 30, 2016 and December 31, 2015, presented net of $18 million and $21 million, respectively, in unamortized debt issuance costs and $14 million and $17 million, respectively, in unamortized original issue discount paid.

[3] On July 1, 2014, the Company entered into a $1,825 million term loan facility maturing July 1, 2021 (the "Term Loan Facility") and a $300 million revolving credit facility maturing July 1, 2019 (the "Revolving Credit Facility") (together with the Term Loan Facility, the "Credit Facilities"). The interest rates applicable to the term loans under the Term Loan Facility are based on a fluctuating rate of interest measured by reference to either, at the Company's option, (i) an adjusted LIBOR (subject to a floor of 1.00 percent) plus a margin of 3.25 percent per annum or (ii) an alternate base rate (subject to a floor of 2.00 percent) plus a margin of 2.25 percent per annum. See Refinancing of Indebtedness below for details of incremental term loans.

[4] As of September 30, 2016 and December 31, 2015, collectively presented net of $49 million and $53 million, respectively, of unamortized fair value adjustments related to purchase accounting, which increases the effective interest rate from the coupon rates shown above.