Goodwill and Other Intangible Assets - Carrying Value and Accumulated Amortization for Each Major Class of Intangible Assets Other Than Goodwill (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Intangible Assets Excluding Goodwill [Line Items]
Gross Carrying Amount	$ 1,076	$ 1,076
Accumulated Amortization	(737)	(721)
Net Carrying Amount	339	355
Carrying value and accumulated amortization for each major class of intangible assets other than goodwill
Non-amortizing intangible assets	1,258	1,254
Intangible assets other than goodwill	1,597	1,609
Trademarks
Carrying value and accumulated amortization for each major class of intangible assets other than goodwill
Non-amortizing intangible assets	790	790
Gaming rights
Carrying value and accumulated amortization for each major class of intangible assets other than goodwill
Non-amortizing intangible assets	215	211
Total Rewards
Carrying value and accumulated amortization for each major class of intangible assets other than goodwill
Non-amortizing intangible assets	$ 253	253
Customer relationships
Intangible Assets Excluding Goodwill [Line Items]
Weighted Average Remaining Useful Life (in years)	4 years 8 months
Gross Carrying Amount	$ 1,030	1,030
Accumulated Amortization	(709)	(693)
Net Carrying Amount	$ 321	337
Contract rights
Intangible Assets Excluding Goodwill [Line Items]
Weighted Average Remaining Useful Life (in years)	6 years 9 months
Gross Carrying Amount	$ 3	3
Accumulated Amortization	(2)	(2)
Net Carrying Amount	$ 1	1
Gaming rights
Intangible Assets Excluding Goodwill [Line Items]
Weighted Average Remaining Useful Life (in years)	6 years 3 months
Gross Carrying Amount	$ 43	43
Accumulated Amortization	(26)	(26)
Net Carrying Amount	$ 17	$ 17