Revenue Recognition - Contract Costs (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Acquisition Costs
Capitalized Contract Cost [Line Items]
Beginning of period balance	$ 64	$ 73
Costs incurred	13	11
Amortization	(14)	(15)
End of period balance	63	69
Fulfillment Costs
Capitalized Contract Cost [Line Items]
Beginning of period balance	47	54
Costs incurred	9	6
Amortization	(9)	(8)
End of period balance	$ 47	$ 52