Segment Information - Revenues (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Earned premiums and fee income	$ 5,151	$ 4,835	$ 10,164	$ 9,533
Net investment income	541	581	1,050	1,090
Net realized gains (losses)	(338)	147	(483)	227
Other revenues	19	26	35	38
Total revenues	5,373	5,589	10,766	10,888
Corporate
Segment Reporting Information [Line Items]
Earned premiums and fee income	13	14	26	26
Commercial Lines | Operating Segments [Member]
Segment Reporting Information [Line Items]
Earned premiums and fee income	2,625	2,352	5,120	4,596
Commercial Lines | Operating Segments [Member] | Workers’ compensation
Segment Reporting Information [Line Items]
Earned premiums and fee income	869	768	1,704	1,506
Commercial Lines | Operating Segments [Member] | Liability
Segment Reporting Information [Line Items]
Earned premiums and fee income	453	402	877	777
Commercial Lines | Operating Segments [Member] | Marine
Segment Reporting Information [Line Items]
Earned premiums and fee income	54	57	115	115
Commercial Lines | Operating Segments [Member] | Package business
Segment Reporting Information [Line Items]
Earned premiums and fee income	449	409	884	802
Commercial Lines | Operating Segments [Member] | Property
Segment Reporting Information [Line Items]
Earned premiums and fee income	212	205	402	405
Commercial Lines | Operating Segments [Member] | Professional liability
Segment Reporting Information [Line Items]
Earned premiums and fee income	182	158	360	313
Commercial Lines | Operating Segments [Member] | Bond
Segment Reporting Information [Line Items]
Earned premiums and fee income	77	71	149	140
Commercial Lines | Operating Segments [Member] | Assumed reinsurance
Segment Reporting Information [Line Items]
Earned premiums and fee income	118	84	218	152
Commercial Lines | Operating Segments [Member] | Automobile
Segment Reporting Information [Line Items]
Earned premiums and fee income	211	198	411	386
Personal Lines | AARP Members [Member]
Segment Reporting Information [Line Items]
Earned premiums and fee income	675	682	1,340	1,360
Personal Lines | Operating Segments [Member]
Segment Reporting Information [Line Items]
Earned premiums and fee income	733	746	1,461	1,488
Personal Lines | Operating Segments [Member] | Property
Segment Reporting Information [Line Items]
Earned premiums and fee income	231	231	460	461
Personal Lines | Operating Segments [Member] | Automobile
Segment Reporting Information [Line Items]
Earned premiums and fee income	502	515	1,001	1,027
Group Benefits | Operating Segments [Member]
Segment Reporting Information [Line Items]
Earned premiums and fee income	1,517	1,427	3,007	2,845
Group Benefits | Operating Segments [Member] | Group disability
Segment Reporting Information [Line Items]
Earned premiums and fee income	828	744	1,634	1,483
Group Benefits | Operating Segments [Member] | Group life
Segment Reporting Information [Line Items]
Earned premiums and fee income	599	604	1,196	1,206
Group Benefits | Operating Segments [Member] | Other
Segment Reporting Information [Line Items]
Earned premiums and fee income	90	79	177	156
Hartford Funds | Operating Segments [Member]
Segment Reporting Information [Line Items]
Earned premiums and fee income	263	296	550	578
Hartford Funds | Operating Segments [Member] | Mutual fund and ETF
Segment Reporting Information [Line Items]
Earned premiums and fee income	243	272	508	531
Hartford Funds | Operating Segments [Member] | Talcott Resolution life and annuity separate accounts [2]
Segment Reporting Information [Line Items]
Earned premiums and fee income	$ 20	$ 24	$ 42	$ 47