Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental cash flow information [Line Items]
Cash payments for interest, net of amounts capitalized	$ 484	$ 499	$ 489
Net cash (receipts) payments for income taxes, net of refunds	20	39	10
Capital expenditures included in accounts payable, accrued expenses and other liabilities	17	8	18
Equity investment consideration received from sale of business	1,241	0	0
Acquisition of subsidiary common stock included in accrued expenses and other liabilities	0	51	0
Seller financing secured mortgages resulting from disposition of assets	0	375	0
Investments in subsidiaries prior to acquiring a controlling interest	0	0	286
Discontinued operations and held for sale
Supplemental cash flow information [Line Items]
Capital expenditures included in accounts payable, accrued expenses and other liabilities	$ 48	$ 72	$ 71