Long-term Debt (Tables)

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments

The following table provides a summary of the Company's outstanding long-term debt and the fair values based on quoted market prices in less active markets as of December 31, 2017 and December 31, 2016:

						Level 2 Fair Value as of
	Principal Amount at Par		Issuance Date	Maturity	Interest Due Dates	December 31, 2017		December 31, 2016
	(in millions)					(in millions)
4.875% Senior Notes	$	1,600	October 2017	April 2028	April 15 and October 15	$	1,571	$	—
3.625% Senior Notes (1)	1,561		May 2017	May 2027	May 15 and November 15	1,575		—
4.375% Senior Notes	1,000		October 2016	November 2026	May 15 and November 15	983		975
5.50% Senior Notes	700		February 2015	February 2022	April 15 and October 15	739		758
5.875% Senior Notes	800		February 2015	February 2025	April 15 and October 15	856		868
5.750% Senior Notes	400		February 2014	March 2024	March 1 and September 1	427		431
5.375% Senior Notes	500		February 2013	February 2021	February 1 and August 1	530		539

(1) Debt is denominated in euro with a €1,300 million aggregate principal amount and is remeasured into U.S. dollars at each balance sheet date. Total proceeds were $1,420.5 million and remeasurement loss on long-term debt was $140.8 million for the year ended December 31, 2017.