Shareholders' equity Share Repurchases (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Jul. 25, 2024	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Jul. 01, 2023	May 19, 2022
May 2022 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount							$ 2,500
Number of shares repurchased			3,674,300		5,684,700
Cost of shares repurchased			$ 724		$ 1,152
Repurchase authorization remaining at end of period			$ 0		$ 0
July 2023 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount						$ 5,000
Number of shares repurchased		2,254,236		3,474,357
Cost of shares repurchased		$ 570		$ 886
Repurchase authorization remaining at end of period		$ 2,808		$ 2,808
Subsequent Event [Member] | July 2023 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased	175,465
Cost of shares repurchased	$ 45
Repurchase authorization remaining at end of period	$ 2,764