Financing Agreements - Narrative (Details) (USD $)	3 Months Ended		9 Months Ended		0 Months Ended	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Feb. 14, 2014 Revolving Credit agreement	Dec. 31, 2013 Revolving Credit agreement	Sep. 30, 2014 Revolving Credit agreement	Sep. 30, 2014 Letter of Credit	Jan. 24, 2014 Letter of Credit	Sep. 30, 2014 ING Bank	Sep. 30, 2014 Lion Connecticut Holdings Debentures Aetna Notes	Sep. 30, 2014 Lion Connecticut Holdings Debentures Aetna Notes Minimum	Sep. 30, 2014 Lion Connecticut Holdings Debentures Aetna Notes Maximum	Jan. 15, 2014 Trust Notes	Jan. 02, 2014 Trust Notes
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis			LIBOR
Basis spread					1.75%	2.00%
Minimum principal outstanding in year two											$ 400,000,000
Minimum principal outstanding in year three											300,000,000
Minimum principal outstanding in year four											200,000,000
Minimum principal outstanding in year five											100,000,000
Minimum principal outstanding in year six											0
Quarterly fee to guarantor of notes if minimum principal balance is not met												0.50%	1.25%
Outstanding par amount of guaranteed debentures	506,100,000		506,100,000
Revolving lines of credit	9,977,900,000		9,977,900,000		3,000,000,000	3,500,000,000			150,000,000	1,275,000,000				500,000,000	565,000,000
Credit facility, sublimit, maximum borrowing capacity					750,000,000
Outstanding borrowings	5,674,400,000		5,674,400,000				0	684,900,000		734,300,000
Payments of financing costs	$ 29,100,000	$ 33,800,000	$ 86,500,000	$ 119,500,000	$ 700,000