Revision of Previously Reported Financial Statements - Statement of Cash Flow (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
OPERATING ACTIVITIES:
Net income (loss)	$ (52.2)	$ (15.2)
Net realized gains / losses	8.8	35.1
Policy acquisition costs deferred	(24.9)	(16.9)
Policy acquisition cost amortization	15.5	16.7
Interest credited	25.9	23.8
Equity in earnings of limited partnerships and other investments	(0.6)	(0.8)
Change in:
Accrued investment income	(6.6)	(5.9)
Deferred income taxes, net	(0.8)	(4.4)
Reinsurance recoverable	(38.1)	26.5
Policy liabilities and accruals	(45.7)	(80.7)
Due to/from related parties	9.4	(13.9)
Other operating activities, net	16.3	17.7
Cash provided by (used for) operating activities	(93.0)	(18.0)
Purchases of:
Available-for-sale debt securities	(329.5)	(151.4)
Available-for-sale equity securities	0	0
Short-term investments	(159.8)	(209.8)
Derivative instruments	(17.5)	(17.7)
Fair value investments	0	0
Sales, repayments and maturities of:
Available-for-sale debt securities	174.5	65.1
Available-for-sale equity securities	0	0
Short-term investments	169.7	99.9
Derivative instruments	19.8	30.1
Fair value investments	0.6	0.9
Contributions to limited partnerships and limited liability corporations	(0.1)	(0.5)
Distributions from limited partnerships and limited liability corporations	0.4	0.7
Policy loans, net	(0.5)	(0.7)
Other investing activities, net	2.1	(1.8)
Cash provided by (used for) investing activities	(140.3)	(185.2)
FINANCING ACTIVITIES:
Policyholder deposits	254.8	230.4
Policyholder withdrawals	(163.8)	(164.4)
Net transfers (to) from separate accounts	73.9	97.1
Cash provided by (used for) financing activities	164.9	163.1
Change in cash and cash equivalents	(68.4)	(40.1)
Cash and cash equivalents, beginning of period	162.3	181.0
Cash and cash equivalents, end of period	93.9	140.9
Supplemental Disclosure of Cash Flow Information
Income taxes (paid) refunded	(21.9)	14.5
Non-Cash Transactions During the Period
Investment exchanges	5.6	8.9
As reported
OPERATING ACTIVITIES:
Net income (loss)		(16.8)
Net realized gains / losses		33.9
Policy acquisition costs deferred		(16.9)
Policy acquisition cost amortization		16.3
Interest credited		23.8
Equity in earnings of limited partnerships and other investments		(0.8)
Change in:
Accrued investment income		(5.9)
Deferred income taxes, net		(3.9)
Reinsurance recoverable		28.3
Policy liabilities and accruals		(78.3)
Due to/from related parties		(13.9)
Other operating activities, net		16.2
Cash provided by (used for) operating activities		(18.0)
Purchases of:
Available-for-sale debt securities		(151.4)
Available-for-sale equity securities		0
Short-term investments		(209.8)
Derivative instruments		(17.7)
Fair value investments		0
Sales, repayments and maturities of:
Available-for-sale debt securities		65.1
Available-for-sale equity securities		0
Short-term investments		99.9
Derivative instruments		30.1
Fair value investments		0.9
Contributions to limited partnerships and limited liability corporations		(0.5)
Distributions from limited partnerships and limited liability corporations		0.7
Policy loans, net		(0.7)
Other investing activities, net		(1.8)
Cash provided by (used for) investing activities		(185.2)
FINANCING ACTIVITIES:
Policyholder deposits		230.4
Policyholder withdrawals		(164.4)
Net transfers (to) from separate accounts		97.1
Cash provided by (used for) financing activities		163.1
Change in cash and cash equivalents		(40.1)
Cash and cash equivalents, beginning of period		181.0
Cash and cash equivalents, end of period		140.9
Supplemental Disclosure of Cash Flow Information
Income taxes (paid) refunded		14.5
Non-Cash Transactions During the Period
Investment exchanges		8.9
Correction of errors
OPERATING ACTIVITIES:
Net income (loss)		1.6
Net realized gains / losses		1.2
Policy acquisition costs deferred		0
Policy acquisition cost amortization		0.4
Interest credited		0
Equity in earnings of limited partnerships and other investments		0
Change in:
Accrued investment income		0
Deferred income taxes, net		(0.5)
Reinsurance recoverable		(1.8)
Policy liabilities and accruals		(2.4)
Due to/from related parties		0
Other operating activities, net		1.5
Cash provided by (used for) operating activities		0
Purchases of:
Available-for-sale debt securities		0
Available-for-sale equity securities		0
Short-term investments		0
Derivative instruments		0
Fair value investments		0
Sales, repayments and maturities of:
Available-for-sale debt securities		0
Available-for-sale equity securities		0
Short-term investments		0
Derivative instruments		0
Fair value investments		0
Contributions to limited partnerships and limited liability corporations		0
Distributions from limited partnerships and limited liability corporations		0
Policy loans, net		0
Other investing activities, net		0
Cash provided by (used for) investing activities		0
FINANCING ACTIVITIES:
Policyholder deposits		0
Policyholder withdrawals		0
Net transfers (to) from separate accounts		0
Cash provided by (used for) financing activities		0
Change in cash and cash equivalents		0
Cash and cash equivalents, beginning of period		0
Cash and cash equivalents, end of period		0
Supplemental Disclosure of Cash Flow Information
Income taxes (paid) refunded		0
Non-Cash Transactions During the Period
Investment exchanges		$ 0