Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 1,398	$ 1,354	$ 4,347	$ 4,136
Other comprehensive income, net of tax
Net unrealized appreciation on securities and derivatives	120	223	401	1,008
Net translation gains (losses) on foreign currencies	109	(127)	4	(195)
Postretirement benefits liability adjustment	14	12	(15)	37
Other comprehensive income, net of tax	243	108	390	850
Total comprehensive income	1,641	1,462	4,737	4,986
Comprehensive income (loss) attributable to noncontrolling interests
Net income attributable to redeemable noncontrolling interest	4	3	12	8
Net income attributable to other noncontrolling interests	6	0	12	1
Other comprehensive (loss) attributable to redeemable noncontrolling interest	(4)	1	(10)	(3)
Total comprehensive income attributable to noncontrolling interests	6	4	14	6
SHAREHOLDERS' COMPREHENSIVE INCOME	$ 1,635	$ 1,458	$ 4,723	$ 4,980