Goodwill & Other Intangible Assets - Goodwill Carrying Value (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Roll Forward]
Beginning balance	$ 1,911,000,000	$ 1,913,000,000
Goodwill, Purchase Accounting Adjustments	0	(2,000,000)
Ending balance	1,911,000,000	1,911,000,000	$ 1,913,000,000
Goodwill, Impairment Loss	0	0	0
Operating Segments | P&C Commercial Lines
Goodwill [Roll Forward]
Beginning balance	659,000,000	661,000,000
Goodwill, Purchase Accounting Adjustments	0	(2,000,000)
Ending balance	659,000,000	659,000,000	661,000,000
Operating Segments | P&C Personal Lines
Goodwill [Roll Forward]
Beginning balance	119,000,000	119,000,000
Goodwill, Purchase Accounting Adjustments	0	0
Ending balance	119,000,000	119,000,000	119,000,000
Operating Segments | Hartford Funds
Goodwill [Roll Forward]
Beginning balance	180,000,000	180,000,000
Goodwill, Purchase Accounting Adjustments	0	0
Ending balance	180,000,000	180,000,000	180,000,000
Operating Segments | Group Benefits [Member]
Goodwill [Roll Forward]
Beginning balance	723,000,000	723,000,000
Goodwill, Purchase Accounting Adjustments	0	0
Ending balance	723,000,000	723,000,000	723,000,000
Corporate
Goodwill [Roll Forward]
Beginning balance	230,000,000	230,000,000
Goodwill, Purchase Accounting Adjustments	0	0
Ending balance	230,000,000	230,000,000	230,000,000
Corporate | Hartford Funds
Goodwill [Roll Forward]
Beginning balance	92,000,000	92,000,000
Ending balance	92,000,000	92,000,000	92,000,000
Corporate | Group Benefits [Member]
Goodwill [Roll Forward]
Beginning balance	138,000,000	138,000,000
Ending balance	$ 138,000,000	$ 138,000,000	$ 138,000,000