Supplemental Cash Flow Information (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Supplemental Cash Flow Information [Line Items]
Cash payments related to operating lease liabilities	[1]	$ 135	$ 145
Interest paid		223	208
Income Taxes Paid		1	0
New ROU assets obtained in exchange for operating lease liabilities		133	36
Increase (decrease) in accounts payable for purchases of property and equipment		(18)	2
Purchase of property and equipment under capital leases and installment purchases		$ 5	$ 9

[1] Excludes the Company's contingent payment pursuant to operating leases, which are recorded as expense in the period such contingencies are resolved.