MD&A - Risk management and control - Market Risk (Detail 2) $ in Millions	Dec. 31, 2020 USD ($)
+1 bp
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	$ (27.2)
Additional tier 1 (AT1) capital instruments	4.2
Total including AT1 capital instruments	(23.0)
+1 bp | CHF
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(5.2)
+1 bp | EUR
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(0.9)
+1 bp | GBP
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	0.2
+1 bp | USD
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(20.7)
+1 bp | Other
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(0.6)
Parallel up
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(5,604.8)	[1]
Additional tier 1 (AT1) capital instruments	815.1	[1]
Total including AT1 capital instruments	(4,789.7)	[1]
Parallel up | CHF
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(735.8)	[1]
Parallel up | EUR
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(164.9)	[1]
Parallel up | GBP
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	48.7	[1]
Parallel up | USD
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(4,612.8)	[1]
Parallel up | Other
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(140.0)	[1]
Parallel down
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	4,956.9	[1]
Additional tier 1 (AT1) capital instruments	(868.4)	[1]
Total including AT1 capital instruments	4,088.5	[1]
Parallel down | CHF
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	832.3	[1]
Parallel down | EUR
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	163.2	[1]
Parallel down | GBP
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(42.0)	[1]
Parallel down | USD
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	3,999.8	[1]
Parallel down | Other
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	3.6	[1]
Steepener
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(849.1)	[2]
Additional tier 1 (AT1) capital instruments	(92.8)	[2]
Total including AT1 capital instruments	(942.0)	[2]
Steepener | CHF
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(369.6)	[2]
Steepener | EUR
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(73.1)	[2]
Steepener | GBP
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(31.7)	[2]
Steepener | USD
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(395.5)	[2]
Steepener | Other
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	20.8	[2]
Flattener
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(394.1)	[3]
Additional tier 1 (AT1) capital instruments	272.8	[3]
Total including AT1 capital instruments	(121.2)	[3]
Flattener | CHF
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	225.5	[3]
Flattener | EUR
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	29.9	[3]
Flattener | GBP
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	40.2	[3]
Flattener | USD
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(630.5)	[3]
Flattener | Other
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(59.3)	[3]
Short-term up
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(2,332.7)	[4]
Additional tier 1 (AT1) capital instruments	573.6	[4]
Total including AT1 capital instruments	(1,759.1)	[4]
Short-term up | CHF
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(74.5)	[4]
Short-term up | EUR
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(20.4)	[4]
Short-term up | GBP
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	56.9	[4]
Short-term up | USD
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(2,188.9)	[4]
Short-term up | Other
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(105.7)	[4]
Short-term down
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	2,435.2	[5]
Additional tier 1 (AT1) capital instruments	(599.0)	[5]
Total including AT1 capital instruments	1,836.2	[5]
Short-term down | CHF
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	79.0	[5]
Short-term down | EUR
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(4.7)	[5]
Short-term down | GBP
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(47.5)	[5]
Short-term down | USD
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	2,397.9	[5]
Short-term down | Other
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	10.5	[5]
UBS AG | +1 bp
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(27.2)
Additional tier 1 (AT1) capital instruments	4.2
Total including AT1 capital instruments	(23.0)
UBS AG | +1 bp | CHF
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(5.2)
UBS AG | +1 bp | EUR
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(0.9)
UBS AG | +1 bp | GBP
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	0.2
UBS AG | +1 bp | USD
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(20.7)
UBS AG | +1 bp | Other
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(0.6)
UBS AG | Parallel up
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(5,604.8)	[1]
Additional tier 1 (AT1) capital instruments	815.1	[1]
Total including AT1 capital instruments	(4,789.7)	[1]
UBS AG | Parallel up | CHF
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(735.8)	[1]
UBS AG | Parallel up | EUR
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(164.9)	[1]
UBS AG | Parallel up | GBP
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	48.7	[1]
UBS AG | Parallel up | USD
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(4,612.8)	[1]
UBS AG | Parallel up | Other
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(140.0)	[1]
UBS AG | Parallel down
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	4,956.9	[1]
Additional tier 1 (AT1) capital instruments	(868.4)	[1]
Total including AT1 capital instruments	4,088.5	[1]
UBS AG | Parallel down | CHF
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	832.3	[1]
UBS AG | Parallel down | EUR
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	163.2	[1]
UBS AG | Parallel down | GBP
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(42.0)	[1]
UBS AG | Parallel down | USD
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	3,999.8	[1]
UBS AG | Parallel down | Other
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	3.6	[1]
UBS AG | Steepener
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(849.1)	[2]
Additional tier 1 (AT1) capital instruments	(92.8)	[2]
Total including AT1 capital instruments	(942.0)	[2]
UBS AG | Steepener | CHF
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(369.6)	[2]
UBS AG | Steepener | EUR
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(73.1)	[2]
UBS AG | Steepener | GBP
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(31.7)	[2]
UBS AG | Steepener | USD
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(395.5)	[2]
UBS AG | Steepener | Other
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	20.8	[2]
UBS AG | Flattener
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(394.1)	[3]
Additional tier 1 (AT1) capital instruments	272.8	[3]
Total including AT1 capital instruments	(121.2)	[3]
UBS AG | Flattener | CHF
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	225.5	[3]
UBS AG | Flattener | EUR
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	29.9	[3]
UBS AG | Flattener | GBP
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	40.2	[3]
UBS AG | Flattener | USD
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(630.5)	[3]
UBS AG | Flattener | Other
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(59.3)	[3]
UBS AG | Short-term up
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(2,332.7)	[4]
Additional tier 1 (AT1) capital instruments	573.6	[4]
Total including AT1 capital instruments	(1,759.1)	[4]
UBS AG | Short-term up | CHF
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(74.5)	[4]
UBS AG | Short-term up | EUR
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(20.4)	[4]
UBS AG | Short-term up | GBP
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	56.9	[4]
UBS AG | Short-term up | USD
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(2,188.9)	[4]
UBS AG | Short-term up | Other
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(105.7)	[4]
UBS AG | Short-term down
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	2,435.2	[5]
Additional tier 1 (AT1) capital instruments	(599.0)	[5]
Total including AT1 capital instruments	1,836.2	[5]
UBS AG | Short-term down | CHF
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	79.0	[5]
UBS AG | Short-term down | EUR
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(4.7)	[5]
UBS AG | Short-term down | GBP
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	(47.5)	[5]
UBS AG | Short-term down | USD
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	2,397.9	[5]
UBS AG | Short-term down | Other
Interest Rate Sensitivity Of Banking Book [Line Items]
Total effect on economic value of equity as per Pillar 3 requirement	$ 10.5	[5]

[1] Rates across all tenors move by ±150 bps for Swiss franc, ±200 bps for euro and US dollar and ±250 bps for pound sterling

[2] Short-term rates decrease and long-term rates increase.

[3] Short-term rates increase and long-term rates decrease.

[4] Short-term rates increase more than long-term rates.

[5] Short-term rates decrease more than long-term rates.