Goodwill And Other Acquired Intangible Assets - Activity in Goodwill (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2021	Dec. 31, 2020
Goodwill [Roll Forward]
Beginning balance, goodwill gross	$ 4,568	$ 3,734
Beginning balance, Accumulated impairment charge	(12)	(12)
Beginning balance, goodwill net	4,556	3,722
Additions/adjustments	95	626
Foreign currency translation adjustments	(61)	208
Ending balance, goodwill gross	4,602	4,568
Ending balance, Accumulated impairment charge	(12)	(12)
Ending balance, goodwill net	4,590	4,556
MIS
Goodwill [Roll Forward]
Beginning balance, goodwill gross	311	315
Beginning balance, Accumulated impairment charge	0	0
Beginning balance, goodwill net	311	315
Additions/adjustments	0	(2)
Foreign currency translation adjustments	1	(2)
Ending balance, goodwill gross	312	311
Ending balance, Accumulated impairment charge	0	0
Ending balance, goodwill net	312	311
MA
Goodwill [Roll Forward]
Beginning balance, goodwill gross	4,257	3,419
Beginning balance, Accumulated impairment charge	(12)	(12)
Beginning balance, goodwill net	4,245	3,407
Additions/adjustments	95	628
Foreign currency translation adjustments	(62)	210
Ending balance, goodwill gross	4,290	4,257
Ending balance, Accumulated impairment charge	(12)	(12)
Ending balance, goodwill net	$ 4,278	$ 4,245

Goodwill, Additions and Adjustments During Period

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of increase (decrease) from foreign currency translation adjustments and purchase accounting adjustments of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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