Employee Benefit Plans - BHE - Employer Contributions (Details) - 3 months ended Mar. 31, 2024 £ 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	$ 5
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 | £			£ 9
Employer contributions	$ 3	£ 2