Employee Benefit Plans - BHE - Employer Contributions (Details) - 3 months ended Mar. 31, 2023 £ in Millions, $ in Millions	USD ($)	GBP (£)	GBP (£)
Other Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	$ 7
Employer contributions	1
U.S. | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year	13
Employer contributions	3
United Kingdom | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected contributions in current fiscal year | £			£ 11
Employer contributions	$ 4	£ 3