Debt and Other Obligations (Debt Purchases and Repayments) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Extinguishment of Debt [Line Items]
Principal amount		$ 750	$ 1,250	$ 1,950
Cash paid		750	1,274	2,089
Gains (losses) on retirement of long-term obligations		0	(28)	(145)
2016 Term Loan A [Member]
Extinguishment of Debt [Line Items]
Principal amount				0
Cash paid				0
Gains (losses) on retirement of long-term obligations	[1]			(1)
5.250% Senior Notes [Member]
Extinguishment of Debt [Line Items]
Principal amount				1,650
Cash paid	[2]			1,789
Gains (losses) on retirement of long-term obligations	[1]			(143)
2015 Tower Revenue Notes 3.222% due 2042 [Member]
Extinguishment of Debt [Line Items]
Principal amount				300
Cash paid	[2]			300
Gains (losses) on retirement of long-term obligations	[1]			(1)
2018 Tower Revenue Notes 3.720% due 2043 [Member]
Extinguishment of Debt [Line Items]
Principal amount			250
Cash paid	[2]		252
Gains (losses) on retirement of long-term obligations	[1]		(3)
3.849% Secured Notes [Member]
Extinguishment of Debt [Line Items]
Principal amount			1,000
Cash paid	[2]		1,022
Gains (losses) on retirement of long-term obligations	[1]		(23)
Revolving Credit Facility [Member]
Extinguishment of Debt [Line Items]
Principal amount			0
Cash paid			0
Gains (losses) on retirement of long-term obligations	[1]		$ (2)
3.150% Senior Notes [Member]
Extinguishment of Debt [Line Items]
Principal amount		750
Cash paid	[2]			$ 750
Gains (losses) on retirement of long-term obligations		$ 0

[1] Inclusive of the write-off of the respective deferred financing costs

[2] Exclusive of accrued interest.