Goodwill and Other Intangible Assets - Other Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 48	$ 48
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	1,080	1,074
Accumulated Amortization	993	953
Net Carrying Amount	$ 87	$ 121
Management contract rights
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Lives	20 years	20 years
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	$ 550	$ 550
Accumulated Amortization	532	504
Net Carrying Amount	$ 18	$ 46
Customer relationship lists
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Lives	20 years	20 years
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	$ 120	$ 120
Accumulated Amortization	91	83
Net Carrying Amount	$ 29	$ 37
Computer software
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Lives	3 years	3 years
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	$ 410	$ 404
Accumulated Amortization	370	366
Net Carrying Amount	$ 40	$ 38