Risk management, funding and liquidity risk and market risk - Key parameters of VaR (Details) - Market risk	12 Months Ended
Sep. 30, 2022
Key parameters of VaR
Holding period	1 day
Confidence level	99.00%
Period of historical data used	1 year

The period of historical data used for Value at Risk.

No definition available.

Name:	webnf_PeriodOfHistoricalDataUsedForVar
Namespace Prefix:	webnf_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration