Long-Term Debt - Receivables Financing Facility (Details) - USD ($)	2 Months Ended	12 Months Ended
	Feb. 22, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Accounts receivable securitized		$ 421,000,000
Total outstanding debt		2,176,000,000	$ 2,648,000,000
Secured Debt | Receivables Financing Facility
Debt Instrument [Line Items]
Facility amount		180,000,000
Total outstanding debt		135,000,000
Proceeds from Accounts Receivable Securitization		145,000,000
Repayments of Accounts Receivable Securitization		10,000,000
Receivable financing facility, interest expense		$ 1,000,000
Receivable financing facility, average interest rate		2.35%
Loans Payable | Term Loan B
Debt Instrument [Line Items]
Prepayments of term loan		$ 493,000,000
Revolving Credit Facility
Debt Instrument [Line Items]
Receivable financing facility, average interest rate		3.39%
Subsequent Event | Loans Payable | Term Loan B
Debt Instrument [Line Items]
Prepayments of term loan	$ 63,000,000