Consolidated Statements Of Operations and Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues
Net premiums written	$ 37,868	$ 33,820	$ 32,275
Increase in unearned premiums	(1,513)	(703)	(985)
Net premiums earned	36,355	33,117	31,290
Net investment income	3,456	3,375	3,426
Net realized gains (losses):
Other-than-temporary impairment (OTTI) losses gross			(90)
Portion of OTTI losses recognized in other comprehensive income (OCI)	0		32
Net OTTI losses recognized in income			(58)
Net realized gains (losses) excluding OTTI losses	1,152	(498)	(472)
Net realized gains (losses) (includes $3, $(281), and $(31) reclassified from AOCI)	1,152	(498)	(530)
Total revenues	40,963	35,994	34,186
Expenses
Losses and loss expenses	21,980	21,710	18,730
Policy benefits	699	784	740
Policy acquisition costs	6,918	6,547	6,153
Administrative expenses	3,136	2,979	3,030
Interest expense	492	516	552
Other (income) expense	(2,365)	(994)	(596)
Amortization of purchased intangibles	287	290	305
Chubb integration expenses	0	0	23
Total expenses	31,147	31,832	28,937
Income before income tax	9,816	4,162	5,249
Income tax expense (includes benefit of $(6), $(36), and nil on unrealized gains and losses reclassified from AOCI)	1,277	629	795
Net income	8,539	3,533	4,454
Other comprehensive income (loss)
Unrealized appreciation (depreciation)	(2,935)	2,311	3,704
Reclassification adjustment for net realized (gains) losses included in net income	(3)	281	31
Other comprehensive income (loss) after reclassification for net realized gains included in net income	(2,938)	2,592	3,735
Change in:
Cumulative foreign currency translation adjustment	(530)	306	13
Postretirement benefit liability adjustment	522	(232)	(76)
Other comprehensive income (loss), before income tax	(2,946)	2,666	3,672
Income tax (expense) benefit related to OCI items	427	(416)	(605)
Other comprehensive income (loss)	(2,519)	2,250	3,067
Comprehensive income	$ 6,020	$ 5,783	$ 7,521
Earnings per share
Basic earnings per share	$ 19.41	$ 7.82	$ 9.77
Diluted earnings per share	$ 19.27	$ 7.79	$ 9.71