Revenue Recognition - Contract Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Acquisition Costs
Capitalized Contract Costs [Roll Forward]
Beginning of period balance	$ 73	$ 86
Costs incurred	49	49
Amortization	(58)	(62)
End of period balance	64	73
Fulfillment Costs
Capitalized Contract Costs [Roll Forward]
Beginning of period balance	54	64
Costs incurred	27	23
Amortization	(34)	(33)
End of period balance	$ 47	$ 54