Business Acquisitions and Divestitures - Identified Assets Acquired and Liabilities Assumed (Rx Savings Solutions) (Details) - USD ($) $ in Millions	Nov. 01, 2022	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Identifiable assets acquired and liabilities assumed:
Goodwill		$ 10,132	$ 9,947	$ 9,451
Rx Savings Solutions, LLC | RxTs Segment
Purchase consideration:
Cash	$ 600
Contingent consideration	92
Total purchase consideration	692
Identifiable assets acquired and liabilities assumed:
Current assets	5
Intangible assets	229
Other non-current assets	3
Current liabilities	(8)
Total identifiable net assets	229
Goodwill	463
Net assets acquired	$ 692