Debt Obligations Senior Secured Credit Facility (Details)	12 Months Ended
	Dec. 31, 2019 USD ($) Rate	Dec. 31, 2018 USD ($)
Debt Instrument [Line Items]
Long-term Debt	$ 3,591,000,000
Letters of Credit Outstanding, Amount	28,000,000
Long-term debt	$ 3,277,000,000	$ 2,980,000,000
Quarterly Payment of Term Loan Principal Amount	0.25%
Increase in Maximum Permitted Leverage Ratio due to Material Acquisitions	0.25
Available Additional Amount of Incremental Term Loan or Incremental Revolving Commitment	$ 150,000,000
Deferred financing fees written off	$ 5,000,000
Period Five [Member]
Debt Instrument [Line Items]
Debt Instrument Covenant Consolidated Leverage Ratio	4.50
Period One [Member]
Debt Instrument [Line Items]
Debt Instrument Covenant Consolidated Leverage Ratio	4.25
Debt Instrument, Covenant, Maximum Spread on Consolidated Leverage Ratio	0.50
Period Two [Member]
Debt Instrument [Line Items]
Debt Instrument Covenant Consolidated Leverage Ratio	1.00
Period Three [Member]
Debt Instrument [Line Items]
Debt Instrument Covenant Consolidated Leverage Ratio	4.00
Debt Instrument, Covenant, Maximum Spread on Consolidated Leverage Ratio	0.50
Period Four [Member]
Debt Instrument [Line Items]
Debt Instrument Covenant Consolidated Leverage Ratio	1.00
Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt Issuance Cost Incurred	$ 15,000,000
Term Loan [Member]
Debt Instrument [Line Items]
Debt Issuance Cost Incurred	18,000,000
Long-term debt	740,000,000	$ 675,000,000	[1]
Total Term Loan Balance Outstanding	$ 748,000,000
Secured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Covenant Interest Coverage Ratio	4.75
Debt Instrument Covenant Maximum Consolidated Leverage Ratio	4.75
Secured Debt [Member] | Revolving [Member]
Debt Instrument [Line Items]
Secured Credit Facility Maximum Borrowing Amount	$ 1,100,000,000
Secured Debt [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Secured Credit Facility Maximum Borrowing Amount	750,000,000
Secured Debt [Member] | Revolving Foreign [Member]
Debt Instrument [Line Items]
Secured Credit Facility Maximum Borrowing Amount	$ 400,000,000
Federal Funds Rate [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.50%
Base Rate [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.00%
Base Rate [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.50%
London Interbank Offered Rate (LIBOR) [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate | Rate	2.50%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Margin for Base Rate Loans	2.25%
Maximum [Member] | EURIBOR [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Margin for Base Rate Loans	1.25%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Margin for Base Rate Loans	1.25%
Minimum [Member] | EURIBOR [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Margin for Base Rate Loans	0.25%

[1] Interest rates are weighted average interest rates as of December 31, 2019 and 2018.