Income taxes - Income tax expense (benefit) reconciliation (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income tax expense reconciliation
Earnings (loss) before income taxes		$ 120,166	$ (30,500)	$ 111,861
Hypothetical income tax expense (benefit) at the U.S. federal statutory rate		25,235	(6,405)	23,491
Dividends received deduction and tax-exempt interest		(678)	(512)	(457)
State income taxes, less U.S. federal income tax effect		603	602	(417)
U.S. income tax credits	[1]	(2,186)	(2,187)	(1,860)
Other differences, net		45		155
Total income taxes		$ 23,019	$ (8,502)	$ 20,912
Effective income tax rate		19.20%	27.90%	18.70%

[1] U.S. income tax credits derive primarily from production tax credits associated with wind-energy generation of BHE and tax credits arising from affordable housing investments.