Basis of Presentation and Accounting Policies Level 4 (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Available-for-sale Securities, Equity Securities	$ 1,121,000,000	$ 1,047,000,000
Other Comprehensive Income (Loss), Net of Tax	(1,257,000,000)	1,007,000,000	$ (2,922,000,000)
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ 2,300,000,000	2,300,000,000
Gross Profit Estimates Term for Most Contracts	20 years
Maximum Uncollateralized Threshold for Derivative Counter Party for Single Level Entity	$ 10,000,000
Participating Dividend to Policyholders	17,000,000	$ 16,000,000	$ 15,000,000
Participating Policies as Percentage of Gross Insurance in Force		1.00%	1.00%
Depreciation, Depletion and Amortization, Nonproduction	164,000,000	$ 198,000,000	$ 174,000,000
Annuity Obligations	746,000,000	776,000,000
Allowance for Doubtful Accounts and Other [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Doubtful Accounts, Premiums and Other Receivables	134,000,000	131,000,000	125,000,000
Property, Liability and Casualty Insurance Product Line [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Premiums Written, Net	0.10	0.09	$ 0.10
Accident and Health Insurance Product Line [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Discounted Deducted From Liabilities	$ 1,100,000,000	$ 1,000,000,000
Weighted Average Discount Rate, Percent	3.24%	3.50%	3.50%
Structured Settlements [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Weighted Average Discount Rate, Percent	6.68%	6.67%
group life term, disability and accident [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Weighted Average Discount Rate, Percent	4.41%	4.53%
HIG_Accounting Standards Update 2016-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Description	In January 2016, the FASB issued updated guidance for the recognition and measurement of financial instruments. The new guidance will require investments in equity securities to be measured at fair value with changes in fair value reported in net income except for those equity securities that result in consolidation or are accounted for under the equity method of accounting. The new guidance will also require a deferred tax asset resulting from net unrealized losses on available-for-sale fixed maturities that are recognized in accumulated other comprehensive income (“OCI”) to be evaluated for recoverability in combination with the Company’s other deferred tax assets. Under existing guidance, the Company measures investments in equity securities, available-for-sale, at fair value with changes in fair value reported in OCI. As required, the Company will adopt the guidance effective January 1, 2018 through a cumulative effect adjustment to retained earnings. Early adoption is not allowed. The impact to the Company will be increased volatility in net income beginning in 2018. Any difference in the evaluation of deferred tax assets may also affect stockholders equity. Cash flows will not be affected. The impact will depend on the composition of the Company’s investment portfolio in the future and changes in fair value of the Company’s investments.
HIG_Accounting Standards Update 2015-2 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Description	The FASB issued updated consolidation guidance. The updates revise existing guidance for when to consolidate VIEs and general partners’ investments in limited partnerships, end the deferral granted for applying the VIE guidance to certain investment companies, and reduce the number of circumstances where a decision maker’s or service provider’s fee arrangement is deemed to be a variable interest in an entity. The updates also modify consolidation guidance for determining whether limited partnerships are VIEs or voting interest entities. This guidance is effective January 1, 2016, and may be applied fully retrospectively or through a cumulative effect adjustment to retained earnings as of the adoption (modified retrospective approach). The Company will adopt the guidance using a modified retrospective approach effective as of January 1, 2016 and upon adoption, the new guidance will not have a material effect on the Company’s Consolidated Financial Statements.
HIG_Accounting Standards Update 2014_09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Description	The FASB issued updated guidance for recognizing revenue. The guidance excludes insurance contracts and financial instruments. Revenue is to be recognized when, or as, goods or services are transferred to customers in an amount that reflects the consideration that an entity is expected to be entitled in exchange for those goods or services, and this accounting guidance is similar to current accounting for many transactions. This guidance is effective retrospectively on January 1, 2018, with a choice of restating prior periods or recognizing a cumulative effect for contracts in place as of the adoption. Early adoption is permitted as of January 1, 2017. The Company has not yet determined its method for adoption or estimated the effect of the adoption on the Company’s Consolidated Financial Statements.
Equity Securities [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Available-for-sale Securities, Equity Securities	$ 839,000,000	$ 699,000,000
Accumulated Other-than-Temporary Impairment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other Comprehensive Income (Loss), Net of Tax	(2,000,000)	$ 7,000,000	$ 35,000,000
Net Income Impact [Member] | HIG_Accounting Standards Update 2016-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Net Income	$ 17,000,000