Goodwill and Acquired Intangible Assets (Schedule of Changes in Goodwill) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2022 USD ($)
Goodwill [Roll Forward]
Balance at beginning of period	$ 8,433
Foreign currency translation adjustments	(95)
Balance at end of period	8,338
Market Technology
Goodwill [Roll Forward]
Balance at beginning of period	2,171
Foreign currency translation adjustments	(5)
Balance at end of period	2,166
Investment Intelligence
Goodwill [Roll Forward]
Balance at beginning of period	2,428
Foreign currency translation adjustments	(35)
Balance at end of period	2,393
Corporate Platforms
Goodwill [Roll Forward]
Balance at beginning of period	469
Foreign currency translation adjustments	(6)
Balance at end of period	463
Market Services
Goodwill [Roll Forward]
Balance at beginning of period	3,365
Foreign currency translation adjustments	(49)
Balance at end of period	$ 3,316