Inventory (Activity Related to Inventory Obligations) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Inventory [Line Items]
Inventory sold, outstanding obligation	$ 117	$ 134	$ 144	$ 198
Purchases	0	2
Payments	(27)	(66)
Accrued expenses and other current liabilities	52		64
Other non-current liabilities	65		80
Avon [Member]
Inventory [Line Items]
Inventory sold, outstanding obligation	11	21	22	32
Purchases	0	0
Payments	(11)	(11)
Accrued expenses and other current liabilities	11		11
Other non-current liabilities	0		11
Las Vegas [Member]
Inventory [Line Items]
Inventory sold, outstanding obligation	44	54	60	68
Purchases	0	1
Payments	(16)	(15)
Accrued expenses and other current liabilities	10		22
Other non-current liabilities	34		38
St. Thomas [Member]
Inventory [Line Items]
Inventory sold, outstanding obligation	0	59	0	98
Purchases	0	1
Payments	0	(40)
Accrued expenses and other current liabilities	0		0
Other non-current liabilities	0		0
Austin [Member]
Inventory [Line Items]
Inventory sold, outstanding obligation	62	0	62	$ 0
Purchases	0	0
Payments	0	$ 0
Accrued expenses and other current liabilities	31		31
Other non-current liabilities	$ 31		$ 31