Other Financial Information - Other Current Assets (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Prepaid Expenses and Other Current Assets [Abstract]
Prepaid expenses	$ 295	$ 290
Income tax receivable	22	7
Materials, supplies and inventory	96	105
Contract assets	45	66
Note receivable	56	0
Receivable for sale of land	56	0
Other	11	53
Total other current assets	829	808
Other current assets reclassified as held for sale	126
Acquisition Costs
Prepaid Expenses and Other Current Assets [Abstract]
Contract costs	142	173
Fulfillment Costs
Prepaid Expenses and Other Current Assets [Abstract]
Contract costs	$ 106	$ 114