Goodwill and Other Purchased Intangible Assets Other Purchased Intangible Assets (Details 2) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Gross customer-related and other intangible assets	$ 3,361	$ 3,362
Less accumulated amortization	(2,783)	(2,579)
Net contract, program and other intangible assets	$ 578	$ 783