Debt Level 1 Debt (Notes)	3 Months Ended
Mar. 31, 2018
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	Senior Notes On March 15, 2018, The Hartford issued $500 of 4.4% senior notes ("4.4% Notes") due March 15, 2048 for net proceeds of approximately $490, after deducting underwriting discounts and expenses from the offering. Interest is payable semi-annually in arrears on March 15 and September 15, commencing September 15, 2018. The Hartford, at its option, can redeem the 4.4% Notes at any time, in whole or in part, at a redemption price equal to the greater of 100% of the principal amount being redeemed or a make-whole amount based on a comparable maturity US Treasury plus 25 basis points, plus any accrued and unpaid interest, except the option of a make-whole payment is not applicable within the final six months before maturity. On March 15, 2018, The Hartford repaid at maturity the $320 principal amount of its 6.3% senior notes. Revolving Credit Facility The Company has a senior unsecured five-year revolving credit facility (the “Credit Facility”) that provides for borrowing capacity of up to $1 billion of unsecured credit through October 31, 2019, subject to amended terms and conditions as described below, available in U.S. Dollars, Euro, Sterling, Canadian Dollars and Japanese Yen. Of the aggregate principal amount available, up to $250 is available to support letters of credit. U.S. Dollar loans will bear interest at the higher of a rate (the prime rate or the Federal Funds Rate plus 0.50% ) plus a basis point spread based on The Hartford’s credit rating and will mature no later than October 31, 2019. Letters of credit issued from the Credit Facility bear a fee based on The Hartford’s credit rating and expire no later than October 31, 2020. The Credit Facility requires the Company to maintain a minimum consolidated net worth excluding AOCI, limits debt based on a maximum senior debt to capitalization ratio of 35%, and includes other customary covenants. As of March 31, 2018, no borrowings were outstanding and $3 in letters of credit were issued under the Credit Facility and the Company was in compliance with all financial covenants. On March 29, 2018, the Company entered into an amendment (the "Amendment") to its Credit Facility that reset the level of the Company’s minimum consolidated net worth financial covenant to $9 billion excluding AOCI from its former $13.5 billion (where net worth was defined as stockholders' equity excluding AOCI and including junior subordinated debt), among other updates. The Amendment also provides for an amended and restated credit agreement that would, upon and subject to certain conditions including consummation of the sale of the life and annuity run-off business and among other changes, (i) decrease the aggregate principal amount of the facility from $1 billion to $750, including a reduction to the amount available for letters of credit from $250 to $100 (ii) change the maturity date to March 29, 2023, and (iii) modify the liens covenant and certain other covenants therein.

Senior Notes

On March 15, 2018, The Hartford issued $500 of 4.4% senior notes ("4.4% Notes") due March 15, 2048 for net proceeds of approximately $490, after deducting underwriting discounts and expenses from the offering. Interest is payable semi-annually in arrears on March 15 and September 15, commencing September 15, 2018. The Hartford, at its option, can redeem the 4.4% Notes at any time, in whole or in part, at a redemption price equal to the greater of 100% of the principal amount being redeemed or a make-whole amount based on a comparable maturity US Treasury plus 25 basis points, plus any accrued and unpaid interest, except the option of a make-whole payment is not applicable within the final six months before maturity.

On March 15, 2018, The Hartford repaid at maturity the $320 principal amount of its 6.3% senior notes.

Revolving Credit Facility

The Company has a senior unsecured five-year revolving credit facility (the “Credit Facility”) that provides for borrowing capacity of up to $1 billion of unsecured credit through October 31, 2019, subject to amended terms and conditions as described below, available in U.S. Dollars, Euro, Sterling, Canadian Dollars and Japanese Yen. Of the aggregate principal amount available, up to $250 is available to support letters of credit. U.S. Dollar loans will bear interest at the higher of a rate (the prime rate or the Federal Funds Rate plus 0.50% ) plus a basis point spread based on The Hartford’s credit rating and will mature no later than October 31, 2019. Letters of credit issued from the Credit Facility bear a fee based on The Hartford’s credit rating and expire no later than October 31, 2020. The Credit Facility requires the Company to maintain a minimum consolidated net worth excluding AOCI, limits debt based on a maximum senior debt to capitalization ratio of 35%, and includes other customary covenants.

As of March 31, 2018, no borrowings were outstanding and $3 in letters of credit were issued under the Credit Facility and the Company was in compliance with all financial covenants.

On March 29, 2018, the Company entered into an amendment (the "Amendment") to its Credit Facility that reset the level of the Company’s minimum consolidated net worth financial covenant to $9 billion excluding AOCI from its former $13.5 billion (where net worth was defined as stockholders' equity excluding AOCI and including junior subordinated debt), among other updates. The Amendment also provides for an amended and restated credit agreement that would, upon and subject to certain conditions including consummation of the sale of the life and annuity run-off business and among other changes, (i) decrease the aggregate principal amount of the facility from $1 billion to $750, including a reduction to the amount available for letters of credit from $250 to $100 (ii) change the maturity date to March 29, 2023, and (iii) modify the liens covenant and certain other covenants therein.