Shareholders' equity Share Repurchases (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended		6 Months Ended
		Jul. 28, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	May 19, 2022	Jul. 19, 2021	Feb. 01, 2021	Nov. 19, 2020
Nov 2019 Stock Repurchase Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased						14,465,400
Cost of shares repurchased						$ 2,440
Repurchase authorization remaining at end of period (1)				$ 65		65
Nov 2020 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount									$ 2,500	$ 1,500
Number of shares repurchased				11,355,400
Cost of shares repurchased				$ 1,921
Repurchase authorization remaining at end of period (1)				$ 65		$ 65
CB_Increase(Decrease)StockRepurchaseProgramAuthorizedAmount									$ 1,000
July 2021 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount								$ 5,000
Number of shares repurchased			5,476,300		10,346,200
Cost of shares repurchased			$ 1,129		$ 2,130
Repurchase authorization remaining at end of period (1)			522		522
May 2022 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount							$ 2,500
Repurchase authorization remaining at end of period (1)	[1]		$ 2,500		$ 2,500
Subsequent Event [Member] | May 2022 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased		1,513,728
Cost of shares repurchased		$ 281
Repurchase authorization remaining at end of period (1)		$ 2,220

[1] As of June 30, 2022, $522 million expired under the July 2021 $5.0 billion share repurchase authorization.