Business Dispositions (Details) (USD $)	0 Months Ended	3 Months Ended		12 Months Ended
	Jan. 02, 2013	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
hig_DisposalGroupNotDiscontinuedOperationGainLossOnDisposalNetOfTax		$ 224,000,000
Reinsurance loss on dispositions		1,492,000,000	0
Separate Accounts Liabilities		66,258,000,000
Revenues		2,402,000,000	342,000,000
Net Income (Loss) Attributable to Parent		380,000,000	289,000,000
Retirement Plans [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Fees and Commissions	355,000,000
hig_DisposalGroupNotDiscontinuedOperationGainLossOnDisposalNetOfTax		45,000,000
Reinsurance loss on dispositions		69,000,000
Goodwill, Written off Related to Sale of Business Unit		87,000,000
Disposal Group Including Discontinued Operation Net Realized Capital losses		634,000,000
Policyholder Liabilities	9,200,000,000
Separate Accounts Liabilities	26,300,000,000
Disposal Group, Including Discontinued Operation, Other Assets	100,000,000
Revenues			211,000,000
Net Income (Loss) Attributable to Parent			18,000,000
Individual Life [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Fees and Commissions	615,000,000
Reinsurance loss on dispositions		0
Goodwill, Written off Related to Sale of Business Unit		163,000,000
Gain (Loss) on Disposition of Assets		927,000,000
Policyholder Liabilities	8,300,000,000
Separate Accounts Liabilities	5,300,000,000
Disposal Group, Including Discontinued Operation, Other Assets	1,800,000,000
Revenues			329,000,000
Net Income (Loss) Attributable to Parent			12,000,000
Goodwill, Impairment Loss				100,000,000
Invested Assets Transferred, Carrying Value	7,600,000,000
Disposal Group, Assets of Business Transferred under Modified Coinsurance Arrangement	1,400,000,000
Other Liabilities	1,900,000,000
Parent [Member] | Retirement [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Reinsurance loss on dispositions		565,000,000
Parent [Member] | Individual Life [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Fees and Commissions	590,000,000
Reinsurance loss on dispositions		927,000,000
Mass Mutual [Member] | Retirement Plans [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Assets of Business Transferred under Contractual Arrangement	$ 9,300,000,000