Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Income tax benefit (expense)	$ 172	$ (3)	$ 164	$ (8)
Net income from discontinued operations, net of tax included in the consolidated statement of operations			329	193
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	26	25	79	78
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Total current assets of businesses held for sale	475		475		$ 553
Total non-current assets of businesses held for sale	1,429		1,429		1,362
Total current liabilities of businesses held for sale	251		251		295
Operating lease liabilities	52		52		59
Total non-current liabilities of businesses held for sale	148		148		$ 140
Discontinued Operations
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Total revenue	285	266	860	743
Total cost of revenue	148	137	431	393
Other operating expenses	63	52	184	155
Operating income	74	77	245	195
Total other income, net	16	1	90	1
Net income from discontinued operations before income taxes	90	78	335	196
Income tax benefit (expense)	(3)	(2)	(6)	(3)
Net income from discontinued operations, net of tax included in the consolidated statement of operations	87	76	329	193
Employee Benefits and Share-based Compensation	6	1	14	3
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Cash and cash equivalents	62	88	62	88
Restricted cash	9	72	9	72
Receivables, net	209	178	209	178
Inventories	79	72	79	72
Prepaid expenses deposits and other current assets	116	143	116	143
Total current assets of businesses held for sale	475	553	475	553
Property and equipment, net	177	173	177	173
Intangible assets and software, net	298	295	298	295
Goodwill	631	562	631	562
Equity investments	258	262	258	262
Other assets	65	70	65	70
Total non-current assets of businesses held for sale	1,429	1,362	1,429	1,362
Total assets of businesses held for sale	1,904	1,915	1,904	1,915
Accounts payable	61	53	61	53
Accrued liabilities and other	190	242	190	242
Total current liabilities of businesses held for sale	251	295	251	295
Operating lease liabilities	35	34	35	34
Other	113	106	113	106
Total non-current liabilities of businesses held for sale	148	140	148	140
Total liabilities of businesses held for sale	$ 399	$ 435	$ 399	$ 435