Revenue Recognition - Capitalized Contract Costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Acquisition Costs
Capitalized Contract Cost [Roll Forward]
Beginning of period balance	$ 215	$ 279	$ 222	$ 289
Costs incurred	41	45	84	89
Amortization	(49)	(53)	(101)	(107)
Change in contract costs held for sale	1	0	3	0
End of period balance	208	271	208	271
Acquisition Costs | Held-for-sale
Capitalized Contract Cost [Roll Forward]
Beginning of period balance	32		34
End of period balance	31		31
Fulfillment Costs
Capitalized Contract Cost [Roll Forward]
Beginning of period balance	187	216	186	216
Costs incurred	41	38	81	75
Amortization	(39)	(37)	(78)	(74)
Change in contract costs held for sale	(1)	0	(1)	0
End of period balance	188	$ 217	188	$ 217
Fulfillment Costs | Held-for-sale
Capitalized Contract Cost [Roll Forward]
Beginning of period balance	32		32
End of period balance	$ 33		$ 33