Stock Compensation Plans - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation cost related to non-vested awards not yet recognized	$ 71
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	2 years
Maximum number of shares that may be issued (in shares)	15,400,000
Shares available for future issuance (in shares)	3,544,674
Award vesting period	3 years
Weighted average grant-date fair value of options granted during period (in shares)	$ 14.88	$ 12.97	$ 11.71
Proceeds from Stock Options Exercised	$ 45	$ 3	$ 24
Share-based Payment Arrangement, Exercise of Option, Tax Benefit	4	0	2
Total intrinsic value of options exercised during period	28	2	16
Share-based Payment Arrangement, Cash Used to Settle Award	0	0	0
Stock-based compensation plans expense	$ 128	$ 116	$ 125
Discount rate for employee stock purchase plan	5.00%
Shares sold during period (in shares)	199,173	340,653	213,472
Share-based Compensation Arrangement by Share-based Payment Award, Cash Received from Shares Issued in Period	$ 13	$ 13	$ 11
Subsidiary Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation plans expense	11	11	11
Subsidiary stock repurchased	$ 16	$ 10	$ 8
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term	3 years	3 years	3 years
Award vesting period	3 years
Stock-based Compensation Arrangement by Share-based Payment Award, Performance Period	3 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	765,000	790,000
Weighted average grant-date fair value (in USD per share)	$ 56.09	$ 55.62	$ 54.07
Total fair value of shares vested during period	$ 105	$ 73	$ 102
Performance Shares \| Dividend Equivalent Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	30,000	11,000
Performance Shares \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Target performance ratio	200.00%
Performance Shares \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Target performance ratio	0.00%
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	4,031,000	3,866,000
Weighted average grant-date fair value (in USD per share)	$ 52.13	$ 54.64	$ 50.49
Restricted Stock Units \| Dividend Equivalent Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	209,000	186,000
The Hartford 2020 Incentive Stock Plan (ISOP) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term	10 years
Maximum number of shares that may be issued (in shares)	11,250,000
Shares available for future issuance (in shares)	9,667,290
The Hartford 2020 Incentive Stock Plan (ISOP) [Member] \| Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Service period	1 year
The Hartford 2020 Incentive Stock Plan (ISOP) [Member] \| Employee Stock Option \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term	10 years

Share-based Compensation Arrangement by Share-based Payment Award, Cash Received from Shares Issued in Period

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Share-based Compensation Arrangements by Share-based Payment Award, Target Performance Ratio

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Stock-based Compensation Arrangement by Share-based Payment Award, Performance Period

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Subsidiary Stock

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Aggregate cash paid by the entity during the period to settle equity instruments granted under equity-based payment arrangements.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of tax benefit from exercise of option under share-based payment arrangement.

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Amount of cash inflow from exercise of option under share-based payment arrangement.

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Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Discount rate from fair value on offering date that participants pay for shares.

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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Number of shares authorized for issuance under share-based payment arrangement.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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