Income taxes - Deferred income taxes (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Deferred income tax liabilities:
Investments – unrealized appreciation	$ 41,150	$ 55,437
Deferred charges reinsurance assumed	2,073	2,234
Property, plant and equipment and equipment held for lease	32,080	31,323
Goodwill and other intangible assets	7,010	6,748
Other	4,695	4,094
Deferred income tax liabilities	87,008	99,836
Deferred income tax assets:
Unpaid losses and loss adjustment expenses	(1,290)	(1,091)
Unearned premiums	(1,196)	(990)
Accrued liabilities	(1,790)	(1,868)
Regulatory liabilities	(1,323)	(1,349)
Other	(5,340)	(4,859)
Deferred income tax assets	(10,939)	(10,157)
Net deferred income tax liability	$ 76,069	$ 89,679