Business Segments (Income statement information) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating revenues
Net earned premiums	$ 2,059	$ 1,962
Net investment income	448	504
Non-insurance warranty revenue	382	338
Other revenues	7	5
Total operating revenues	2,896	2,809
Claims, Benefits and Expenses
Net incurred claims and benefits	1,449	1,500
Policyholders’ dividends	6	6
Amortization of deferred acquisition costs	344	359
Non-insurance warranty expense	354	311
Other insurance related expenses	291	255
Other expenses	63	57
Total claims, benefits and expenses	2,507	2,488
Core income (loss) before income tax	389	321
Income tax (expense) benefit on core income (loss)	(73)	(58)
Core income (loss)	316	263
Net investment gains (losses)	(11)	57
Income tax (expense) benefit on net investment gains (losses)	8	(8)
Net investment gains (losses), after tax	(3)	49
Net income (loss)	313	312
Operating Segments | Specialty
Operating revenues
Net earned premiums	772	735
Net investment income	103	117
Non-insurance warranty revenue	382	338
Other revenues	1	0
Total operating revenues	1,258	1,190
Claims, Benefits and Expenses
Net incurred claims and benefits	445	427
Policyholders’ dividends	1	1
Amortization of deferred acquisition costs	157	154
Non-insurance warranty expense	354	311
Other insurance related expenses	81	70
Other expenses	13	11
Total claims, benefits and expenses	1,051	974
Core income (loss) before income tax	207	216
Income tax (expense) benefit on core income (loss)	(44)	(46)
Core income (loss)	163	170
Operating Segments | Commercial
Operating revenues
Net earned premiums	904	855
Net investment income	118	148
Non-insurance warranty revenue	0	0
Other revenues	8	5
Total operating revenues	1,030	1,008
Claims, Benefits and Expenses
Net incurred claims and benefits	573	639
Policyholders’ dividends	5	5
Amortization of deferred acquisition costs	148	153
Non-insurance warranty expense	0	0
Other insurance related expenses	130	115
Other expenses	7	9
Total claims, benefits and expenses	863	921
Core income (loss) before income tax	167	87
Income tax (expense) benefit on core income (loss)	(35)	(18)
Core income (loss)	132	69
Operating Segments | International
Operating revenues
Net earned premiums	264	252
Net investment income	14	14
Non-insurance warranty revenue	0	0
Other revenues	(1)	0
Total operating revenues	277	266
Claims, Benefits and Expenses
Net incurred claims and benefits	158	155
Policyholders’ dividends	0	0
Amortization of deferred acquisition costs	39	52
Non-insurance warranty expense	0	0
Other insurance related expenses	47	35
Other expenses	1	(5)
Total claims, benefits and expenses	245	237
Core income (loss) before income tax	32	29
Income tax (expense) benefit on core income (loss)	(6)	(5)
Core income (loss)	26	24
Operating Segments | Life & Group
Operating revenues
Net earned premiums	120	120
Net investment income	212	219
Non-insurance warranty revenue	0	0
Other revenues	(1)	1
Total operating revenues	331	340
Claims, Benefits and Expenses
Net incurred claims and benefits	281	281
Policyholders’ dividends	0	0
Amortization of deferred acquisition costs	0	0
Non-insurance warranty expense	0	0
Other insurance related expenses	31	25
Other expenses	3	2
Total claims, benefits and expenses	315	308
Core income (loss) before income tax	16	32
Income tax (expense) benefit on core income (loss)	7	4
Core income (loss)	23	36
Operating Segments | Corporate & Other
Operating revenues
Net earned premiums	(1)	0
Net investment income	1	6
Non-insurance warranty revenue	0	0
Other revenues	2	1
Total operating revenues	2	7
Claims, Benefits and Expenses
Net incurred claims and benefits	(8)	(2)
Policyholders’ dividends	0	0
Amortization of deferred acquisition costs	0	0
Non-insurance warranty expense	0	0
Other insurance related expenses	2	10
Other expenses	41	42
Total claims, benefits and expenses	35	50
Core income (loss) before income tax	(33)	(43)
Income tax (expense) benefit on core income (loss)	5	7
Core income (loss)	(28)	(36)
Eliminations
Operating revenues
Net earned premiums	0	0
Net investment income	0	0
Non-insurance warranty revenue	0	0
Other revenues	(2)	(2)
Total operating revenues	(2)	(2)
Claims, Benefits and Expenses
Net incurred claims and benefits	0	0
Policyholders’ dividends	0	0
Amortization of deferred acquisition costs	0	0
Non-insurance warranty expense	0	0
Other insurance related expenses	0	0
Other expenses	(2)	(2)
Total claims, benefits and expenses	(2)	(2)
Core income (loss) before income tax	0	0
Income tax (expense) benefit on core income (loss)	0	0
Core income (loss)	$ 0	$ 0