Shareholders' equity (Detail) $ / shares in Units, $ in Millions			12 Months Ended
	Aug. 04, 2022 shares	Jan. 17, 2022 shares	Dec. 31, 2022 SFr / shares shares	Dec. 31, 2021 SFr / shares shares	Dec. 31, 2020 shares	May 31, 2022 $ / shares	May 19, 2022 USD ($)	Jul. 19, 2021 USD ($)	May 31, 2021 $ / shares	Feb. 01, 2021 USD ($)	Nov. 19, 2020 USD ($)	May 31, 2020 $ / shares	Nov. 21, 2019 USD ($)
Stockholders' Equity Note [Abstract]
Common Stock, Dividend Rate Approved | $ / shares						$ 0.83			$ 0.80			$ 0.78
The number of votes associated with one Common Share			one
Annual dividend per share approved by shareholders | $ / shares						$ 3.32			$ 3.20			$ 3.12
Authorized Share Capital [Line Items]
Common Shares, par value | SFr / shares			SFr 24.15	SFr 24.15
Treasury Stock, Shares, Retired | shares	13,179,100	14,465,400	27,644,500	3,584,150	2,178,600
The maximum ownership percentage for voting allowed for any one shareholder			10.00%
General Purpose
Authorized Share Capital [Line Items]
Authorized share capital for future issuance | shares			200,000,000
Issuance of Debt
Authorized Share Capital [Line Items]
Authorized share capital for future issuance | shares			33,000,000
Employee Benefit Plans
Authorized Share Capital [Line Items]
Authorized share capital for future issuance | shares			25,410,929
Nov 2019 Stock Repurchase Plan [Member]
Authorized Share Capital [Line Items]
Stock repurchase program authorized amount													$ 1,500
Nov 2020 Stock Repurchase Plan [Member]
Authorized Share Capital [Line Items]
Stock repurchase program authorized amount										$ 2,500	$ 1,500
CB_Increase(Decrease)StockRepurchaseProgramAuthorizedAmount										$ 1,000
July 2021 Stock Repurchase Plan
Authorized Share Capital [Line Items]
Stock repurchase program authorized amount								$ 5,000
2022 Stock Repurchase Plan
Authorized Share Capital [Line Items]
Stock repurchase program authorized amount							$ 2,500