Accounting Policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) segment reporting_unit	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Property, Plant and Equipment [Line Items]
Number of reportable segments | segment	4
Total revenue	$ (8,297,000,000)	$ (7,442,000,000)	$ (6,699,000,000)
Contract assets	9,000,000	7,000,000
Revenues recognized	2,100,000,000
Remaining performance obligations	2,700,000,000
Capitalized contract costs	$ 137,000,000	129,000,000
Capitalized contract cost amortization period	5 years
Market value of cash and cash equivalents	$ 6,497,000,000	4,108,000,000
Restricted cash	8,000,000	14,000,000
Gross deferred technology costs	216,000,000	209,000,000
Accumulated amortization of deferred technology costs	173,000,000	150,000,000
Fair value of our long-term debt borrowings	$ 4,400,000,000	4,600,000,000
Option to extend lease period	12 years
Period of options to terminate lease	1 year
Number of reporting units | reporting_unit	4
Goodwill impairment loss	$ 0	0	0
Impairment of intangible assets	0	0	0
Cost of advertisement	39,000,000	29,000,000	34,000,000
Undistributed accumulated earnings of foreign subsidiary	2,900,000,000
Undistributed earnings of foreign subsidiaries reinvested indefinitely	$ 800,000,000
Minimum
Property, Plant and Equipment [Line Items]
Remaining lease terms	1 year
Minimum | Software and Software Development Costs
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	3 years
Minimum | Building and Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	15 years
Minimum | Equipment and Furniture
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	2 years
Maximum
Property, Plant and Equipment [Line Items]
Remaining lease terms	12 years
Maximum | Software and Software Development Costs
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	7 years
Maximum | Building and Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	40 years
Maximum | Equipment and Furniture
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	10 years
Non-transaction
Property, Plant and Equipment [Line Items]
Total revenue	$ (1,698,000,000)	(1,500,000,000)	(1,408,000,000)
Elimination
Property, Plant and Equipment [Line Items]
Total revenue	146,000,000	137,000,000	128,000,000
Elimination | Non-transaction
Property, Plant and Equipment [Line Items]
Total revenue	$ 146,000,000	$ 137,000,000	$ 128,000,000