Revenue Recognition - Capitalized Contract Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Acquisition Costs
Capitalized Contract Cost [Roll Forward]
Beginning of period balance	$ 289	$ 326
Costs incurred	176	181
Amortization	(209)	(218)
Reclassified as held for sale	(34)
End of period balance	222	289
Fulfillment Costs
Capitalized Contract Cost [Roll Forward]
Beginning of period balance	216	221
Costs incurred	151	141
Amortization	(149)	(146)
Reclassified as held for sale	(32)
End of period balance	$ 186	$ 216