Revenue Recognition - Contract with Customer, Asset and Liability (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Capitalized Contract Cost [Line Items]
Customer receivables	$ 1,493	$ 1,889
Contract assets	73	108
Contract liabilities	680	950
Accounts receivable, gross	1,600	2,100
Allowance for doubtful accounts receivable	102	$ 174
Disposal Group, Held-for-sale, Not Discontinued Operations
Capitalized Contract Cost [Line Items]
Customer receivables	288
Contract assets	9
Contract liabilities	$ 161