Supplemental Unaudited Quarterly Financial Information Consolidated Statements of Cash Flows (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2013		Jun. 30, 2013	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
OPERATING ACTIVITIES:
Net income (loss)	$ (20.4)	[1]	$ (15.8)	$ (31.0)	$ 55.7	$ (137.7)	$ (20.0)
Net realized investment (gains) losses	17.4		6.7	9.5
Policy acquisition costs deferred	(17.2)		(33.5)	(49.6)	(66.7)	(69.2)	(100.7)
Policy acquisition cost amortization	14.0		40.6	62.8	88.4	103.5	109.5
Interest credited	18.4		40.1	64.0	91.2	69.5	60.9
Equity in earnings of limited partnerships and other investments	0.8		(0.1)	(0.3)	(0.4)	(0.1)	(0.2)
Accrued investment income	(6.8)		(3.7)	(8.5)	(7.2)	(8.5)	(12.2)
Deferred income taxes	0		0	0	0	(13.4)	(6.9)
Receivables	6.4		7.6	1.9	7.6	(3.5)	(3.2)
Reinsurance recoverable	(17.0)		(28.4)	(57.7)	(73.5)	(26.1)	(7.7)
Policy liabilities and accruals	(55.5)		(59.5)	(70.7)	(224.0)	(56.4)	(128.3)
Due to/from affiliate	4.5		1.3	(0.4)	0.5	(7.5)	21.1
Other operating activities, net	3.6		(4.4)	7.4	1.3	(38.3)	(54.0)
Cash provided by (used for) operating activities	(51.8)		(49.1)	(72.6)	(130.5)	(165.4)	(122.3)
INVESTING ACTIVITIES:
Available-for-sale debt securities	(155.0)		(429.8)	(672.3)	(985.6)	(852.8)	(1,133.7)
Short-term investments	(224.8)		(224.8)	(224.8)	(324.8)	(574.7)	(325.5)
Derivative instruments	(35.1)		(50.1)	(62.7)	(89.0)	(98.1)	(46.1)
Fair value investments	(9.8)		(14.6)	(21.1)	(21.1)	(5.7)	(34.3)
Available-for-sale debt securities	73.4		151.3	261.2	389.0	438.1	250.1
Short-term investments	244.9		304.8	414.8	489.8	425.8	288.3
Derivative instruments	7.7		15.8	27.4	42.9	26.7	63.8
Fair value investments	1.7		3.7	5.7	10.1	12.4	7.7
Contributions to limited partnerships	(0.3)		(0.4)	(3.5)	(4.3)	(2.1)	(1.2)
Distributions from limited partnerships	0		0.1	0.4	7.8	0.3	0.1
Policy loans, net	0.2		(0.6)	(2.7)	(2.8)	3.9	(2.9)
Other investing activities, net	0.1		0.1	0.1	0.7	(1.0)	(0.6)
Cash provided by (used for) investing activities	(97.0)		(244.5)	(277.5)	(487.3)	(627.2)	(934.3)
FINANCING ACTIVITIES:
Policyholder deposit fund deposits	247.2		469.9	690.7	920.8	1,074.7	1,225.4
Policyholder deposit fund withdrawals	(135.3)		(280.0)	(434.6)	(605.2)	(513.8)	(465.0)
Net transfers to/from separate accounts	70.0		144.5	229.0	325.1	265.3	311.6
Cash provided by (used for) financing activities	181.9		334.4	485.1	715.7	826.2	1,072.0
Change in cash and cash equivalents	33.1		40.8	135.0	97.9	33.6	15.4
Cash and cash equivalents, beginning of year	83.1		83.1	83.1	83.1	49.5	34.1
Cash and cash equivalents, end of year	116.2		123.9	218.1	181.0	83.1	49.5
Supplemental Disclosure of Cash Flow Information
Income taxes paid (refunded)	(3.7)		(9.0)	(25.5)	(24.9)	40.9	(2.5)
Investment exchanges	$ 19.0		$ 29.6	$ 30.5	$ 33.4	$ 28.6	$ 26.4

[1] Results for the quarter ended March 31, 2013 include $3.2 million of income (loss) related to out of period adjustments. Such amounts are not material to any period presented.