Income taxes - Deferred taxes (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Deferred tax liabilities:
Investments – unrealized appreciation	$ 55,437	$ 40,181
Deferred charges reinsurance assumed	2,234	2,613
Property, plant and equipment and equipment held for lease	31,323	30,203
Goodwill and other intangible assets	6,748	6,753
Other	4,094	3,736
Deferred tax liabilities	99,836	83,486
Deferred tax assets:
Unpaid losses and loss adjustment expenses	(1,091)	(1,135)
Unearned premiums	(990)	(900)
Accrued liabilities	(1,868)	(2,193)
Regulatory liabilities	(1,349)	(1,421)
Other	(4,859)	(4,576)
Deferred tax assets	(10,157)	(10,225)
Net deferred tax liability	$ 89,679	$ 73,261