Financing Agreements - Additional Information (Details) - USD ($)							3 Months Ended
	Mar. 31, 2018		Sep. 18, 2017	Sep. 14, 2017	Aug. 17, 2017	Apr. 04, 2017	Mar. 31, 2018		Dec. 31, 2017	[1]
Debt Instrument [Line Items]
Loss on extinguishment of debt						$ 6,000,000
Line of Credit [Member]
Debt Instrument [Line Items]
Current aggregate facility	$ 275,000,000						$ 275,000,000
Revolving Facility [Member]
Debt Instrument [Line Items]
Current aggregate facility	600,000,000						$ 600,000,000
Deferred financing payments					$ 2,000,000
Fronting fee rate							0.125%
Amount outstanding	0						$ 0
Utilized for letters of credit	22,000,000						22,000,000
Available borrowing capacity	578,000,000						578,000,000
Revolving Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Amount that may be applied to letters of credit	$ 275,000,000						$ 275,000,000
Senior Notes Due September 2021 [Member]
Debt Instrument [Line Items]
Senior notes redeemed			$ 350,000,000			$ 100,000,000
Debt redemption price			102.688%			104.031%
Loss on extinguishment of debt			$ 13,000,000
Redemption premium			10,000,000			$ 4,000,000
Write-off of deferred financing costs			$ 3,000,000			1,000,000
Senior Notes Due April 2025 [Member]
Debt Instrument [Line Items]
Senior notes issued						$ 400,000,000
Interest rate	5.75%	[1]				5.75%	5.75%	[1]	5.75%
Net proceeds						$ 394,000,000
Financing costs						6,000,000
Senior Notes Due April 2025 [Member] | Cash Flow Hedging [Member]
Debt Instrument [Line Items]
Interest rate	5.75%						5.75%
Derivative, fixed interest rate	3.85%						3.85%
Senior Notes Due April 2025 [Member] | Currency Swap [Member] | Cash Flow Hedging [Member]
Debt Instrument [Line Items]
Derivative, fixed interest rate	3.85%						3.85%
Other indebtedness [Member]
Debt Instrument [Line Items]
Redemption premium						$ 1,000,000
Term Facility [Member]
Debt Instrument [Line Items]
Net proceeds				$ 274,000,000
Financing costs				$ 1,000,000
Periodic payments as a percentage of the initial principal amount	1.5625%
Interest rate at period end	4.052%						4.052%

[1] In conjunction with the issuance of the April 2025 Notes we entered into 8-year fixed-to-fixed cross-currency swaps which have the effect of economically converting the April 2025 Notes to euro-denominated debt at a fixed rate of 3.850%. In conjunction with the issuance of the June 2026 Notes we entered into 10-year fixed-to-fixed cross-currency swaps which have the effect of economically converting the June 2026 Notes to euro-denominated debt at a fixed rate of 5.140%. See Note 14 for additional information.