Employee Benefit Plans Level 4 Benefit Payments (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014
Prescription Drug Subsidy Receipts, Rolling Maturity [Abstract]
Prescription Drug Subsidy Receipts, Next Twelve Months	$ 3
Prescription Drug Subsidy Receipts, Year Two	3
Prescription Drug Subsidy Receipts, Year Three	3
Prescription Drug Subsidy Receipts, Year Four	3
Prescription Drug Subsidy Receipts, Year Five	3
Prescription Drug Subsidy Receipts, after Year Five	18
Prescription Drug Subsidy Receipts Net	(33)hig_PrescriptionDrugSubsidyReceiptsNet
Pension Plan [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Rolling Maturity [Abstract]
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	318
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	324
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	327
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	332
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	338
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	1,735
Net Defined Benefit Plan Expected Future Benefit Payments	(3,374)
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Rolling Maturity [Abstract]
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	42
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	40
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	38
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	35
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	32
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	123
Net Defined Benefit Plan Expected Future Benefit Payments	$ (310)

Net defined benefit plan expected future benefit payments Total.

No definition available.

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- Definition

Prescription drug subsidy receipts, net.

+ References

No definition available.

+ Details

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- Definition

Amount of benefits from a defined benefit plan expected to be paid in the five fiscal years after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of benefits from a defined benefit plan expected to be paid in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of benefits from a defined benefit plan expected to be paid in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of benefits from a defined benefit plan expected to be paid in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of benefits from a defined benefit plan expected to be paid in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of benefits from a defined benefit plan expected to be paid in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of the prescription drug subsidy receipts to be received after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 60

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6414203&loc=d3e39716-114964

+ Details

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- Definition

Amount of the prescription drug subsidy receipts to be received in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of the prescription drug subsidy receipts to be received in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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- Definition

Amount of the prescription drug subsidy receipts to be received in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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- Definition

Amount of the prescription drug subsidy receipts to be received in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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- Definition

Amount of the prescription drug subsidy receipts to be received in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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