Intangible Assets Including Goodwill - Intangible Assets by Class (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Intangible asset balances by major asset class
Gross Carrying Amount	$ 169	$ 159
Accumulated Amortization	(122)	(99)
Net Carrying Amount	47	60
Capitalized software
Intangible asset balances by major asset class
Gross Carrying Amount	17	7
Accumulated Amortization	(10)	(4)
Net Carrying Amount	7	3
Client relationships
Intangible asset balances by major asset class
Gross Carrying Amount	130	130
Accumulated Amortization	(91)	(77)
Net Carrying Amount	39	53
Completed technology
Intangible asset balances by major asset class
Gross Carrying Amount	20	20
Accumulated Amortization	(19)	(17)
Net Carrying Amount		3
Patents/trademarks
Intangible asset balances by major asset class
Gross Carrying Amount	2	2
Accumulated Amortization	$ (2)	$ (2)