Related parties (Detail 3) SFr in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2020 CHF (SFr)	[2]	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Loans Advances And Mortgages To Key Management Personnel [Line Items]
Balance at the beginning of the year	[1],[3]	SFr 32		$ 33	$ 34
Additions	[1]			14	9
Reductions	[1]			(8)	(11)
Balance at the end of the year	[1],[3]	34		38	33
UBS AG
Loans Advances And Mortgages To Key Management Personnel [Line Items]
Balance at the beginning of the year	[1],[4]	22		23	28
Additions	[1]			13	6
Reductions	[1]			(5)	(11)
Balance at the end of the year	[1],[4]	SFr 28		$ 31	$ 23

[1] All loans are secured loans

[2] Swiss franc amounts disclosed represent the respective US dollar amounts translated at the relevant year-end closing exchange rate.

[3] There were no unused uncommitted credit facilities as of 31 December 2020 and 31 December 2019.

[4] There were no unused uncommitted credit facilities as of 31 December 2020 and 31 December 2019.