Accounts Receivable, net (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts	$ (2)	$ (2)
Accounts receivable, net	627	541
Trade Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross, current	453	285
Credit Card Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross, current	129	160
Vendor receivables for rebates, branding and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross, current	6	29
Other Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross, current	$ 41	$ 69