Debt and Other Obligations Extinguishment of Debt (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2022		Mar. 31, 2021
Extinguishment of Debt [Line Items]
Principal amount		$ 1,250
Cash paid	[1]	1,274
Gains (losses) on retirement of long-term obligations		(26)	[2]	$ (143)
3.849% Secured Notes [Member]
Extinguishment of Debt [Line Items]
Principal amount		1,000
Cash paid	[1]	1,022
Gains (losses) on retirement of long-term obligations	[2]	23
2018 Tower Revenue Notes 3.720% due 2043 [Member]
Extinguishment of Debt [Line Items]
Principal amount		250
Cash paid	[1]	252
Gains (losses) on retirement of long-term obligations	[2]	$ 3

[1] Exclusive of accrued interest.

[2] Inclusive of the write off of respective deferred financing costs.