Supplemental Cash Flow Information (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplemental Cash Flow Information [Abstract]
Operating Lease, Payments	[1],[2]	$ 541	$ 0	$ 0
Interest paid		661	619	547
Income taxes paid (refund)		16	17	16
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	[2]	431	0	0
Increase (Decrease) in accounts payable for purchases of property and equipment		2	29	2
Purchase of property and equipment under capital leases and installment purchases		33	40	32
Preferred Stock Dividends Accrued but not Paid		$ 0	$ 0	$ 28

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

[2] See "Recently Adopted Accounting Pronouncements" in note 3 for a discussion of the recently adopted new lease standard.