Stockholders' equity (Details Textual) (Details) $ / shares in Units, shares in Millions, $ in Millions		1 Months Ended			3 Months Ended
	Feb. 25, 2022 USD ($) shares	Jun. 30, 2022 $ / shares	Mar. 31, 2022 USD ($) $ / shares	Dec. 31, 2021 $ / shares	Mar. 31, 2022 USD ($) $ / shares	Mar. 31, 2021 USD ($) $ / shares shares	Mar. 31, 2020 USD ($) shares	Feb. 24, 2022 financial_institution
Class of Stock [Line Items]
Stock repurchased, Shares | shares						24.6	3.7
Stock repurchased						$ 5,410	$ 865
Repurchases of common stock					$ 6,310	$ 865
Amount available for stock repurchases under a board approved stock repurchase plan			$ 4,600		$ 4,600
Dividends declared per share (in usd per share) | $ / shares			$ 1.94	$ 1.94	$ 1.94	$ 1.76
Dividends paid per share (in usd per share) | $ / shares			$ 1.94
Accumulated deficit [Member]
Class of Stock [Line Items]
Repurchases of common stock					$ 5,410	$ 865
Common stock and additional paid-in capital [Member]
Class of Stock [Line Items]
Repurchases of common stock					$ 900
Accelerated stock repurchase agreement
Class of Stock [Line Items]
Stock repurchased, Shares | shares	23.3
Stock repurchased	$ 6,000
Number of Third-Party Financial Institutions | financial_institution								3
Accelerated stock repurchase agreement | Accumulated deficit [Member]
Class of Stock [Line Items]
Repurchases of common stock	5,100
Accelerated stock repurchase agreement | Common stock and additional paid-in capital [Member]
Class of Stock [Line Items]
Repurchases of common stock	$ 900
Forecast [Member]
Class of Stock [Line Items]
Dividends paid per share (in usd per share) | $ / shares		$ 1.94