Goodwill and Intangible Assets, Net - Narrative - Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Line Items]
Goodwill impairment charge	$ 0	$ 0	$ 0	$ 69
Amortization expense of intangible assets	80	$ 108	262	320
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
Estimated annual amortization expense, remainder of 2022	70		70
Estimated annual amortization expense, 2023	226		226
Estimated annual amortization expense, 2024	215		215
Estimated annual amortization expense, 2025	209		209
Estimated annual amortization expense, 2026	177		177
Estimated annual amortization expense, thereafter	$ 1,200		$ 1,200
International (1) | Retail Pharmacy Reporting Unit
Goodwill [Line Items]
Goodwill impairment charge				$ 69