Accumulated Other Comprehensive Income (Loss) - Changes in AOCI, including Reclassification Adjustments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012
Available-for-sale securities, Before-Tax Amount:
Net unrealized gains/losses on Other			$ 0	[1]	$ 0	[1]
Adjustments for amounts recognized in Net realized capital gains (losses) in the Condensed Consolidated Statements of Operations			8.4		58.6
DAC/VOBA and sales inducements			447.5	[2]	(231.0)	[2]
Premium deficiency reserve adjustment			62.9		(52.2)
Net realized gains/losses on available-for-sale securities			(792.5)		418.7
Available-for-sale securities, Income Tax:
Net unrealized gains/losses on Other			0	[1]	0	[1]
Adjustments for amounts recognized in Net realized capital gains (losses) in the Condensed Consolidated Statements of Operations			(2.9)		(19.9)
DAC/VOBA and sales inducements			(156.6)		85.5
Premium deficiency reserve adjustment			(22.0)		17.7
Net realized gains/losses on available-for-sale securities			302.9		(142.1)
Available-for-sale securities, After-Tax Amount:
Net unrealized gains/losses on Other			0	[1]	0	[1]
Adjustments for amounts recognized in Net realized capital gains (losses) in the Condensed Consolidated Statements of Operations			5.5		38.7
DAC/VOBA and sales inducements			290.9		(145.5)
Premium deficiency reserve adjustment			40.9		(34.5)
Net realized gains/losses on available-for-sale securities			(489.6)		276.6
Derivatives, Before-Tax Amount:
Net unrealized capital gains/losses arising during the period, Before-Tax Amount			(68.0)	[3]	47.3	[3]
Adjustments for amounts recognized in Net investment income in the Condensed Consolidated Statements of Operations			1.6		0
Net unrealized gains/losses on derivatives			(66.4)		47.3
Derivatives, Income Tax:
Net unrealized capital gains/losses arising during the period, Income Tax			23.8		(16.1)
Adjustments for amounts recognized in Net investment income in the Condensed Consolidated Statements of Operations			(0.6)		0
Net unrealized gains/losses on derivatives			23.2		(16.1)
Derivatives, After-Tax Amount:
Net unrealized capital gains/losses arising during the period, After-Tax Amount			(44.2)		31.2
Adjustments for amounts recognized in Net investment income in the Condensed Consolidated Statements of Operations			1.0		0
Net unrealized gains/losses on derivatives			(43.2)		31.2
OTTI:
Other-than-temporary impairments	2.0	7.0	3.4		10.6
Change in OTTI, Income Tax			(1.2)		(3.7)
Change in OTTI, After-Tax Amount			2.2		6.9
Pension and other post-employment benefit liability, Before-Tax Amount:
Amortization of prior service cost recognized in Operating expenses in the Condensed Consolidated Statements of Operations			(1.7)	[4]	(1.7)	[4]
Net pension and other post-employment benefit liability	(0.7)	(0.6)	(1.7)		(1.7)
Other comprehensive income (loss), before tax	(51.6)	260.3	(860.6)		464.3
Pension and other post-employment benefit liability, Income Tax:
Amortization of prior service cost recognized in Operating expenses in the Condensed Consolidated Statements of Operations			0.6		0.6
Net pension and other post-employment benefit liability			0.6		0.6
Other comprehensive income (loss)	(45.7)	98.2	(326.7)		157.6
Pension and other post-employment benefit liability, After-Tax Amount:
Amortization of prior service cost recognized in Operating expenses in the Condensed Consolidated Statements of Operations			(1.1)		(1.1)
Net pension and other post-employment benefit liability			1.1		1.1
Other comprehensive income (loss), after tax	(5.9)	162.1	(533.9)		306.7
Fixed maturities
Available-for-sale securities, Before-Tax Amount:
Net unrealized gains/losses on securities			(1,317.3)		633.5
Available-for-sale securities, Income Tax:
Net unrealized gains/losses on securities			486.5	[5]	(222.0)
Available-for-sale securities, After-Tax Amount:
Net unrealized gains/losses on securities			(830.8)		411.5
Fixed maturities | Deferred Tax Asset Valuation Allowance
Available-for-sale securities, Income Tax:
Net unrealized gains/losses on securities			(30.5)
Equity securities
Available-for-sale securities, Before-Tax Amount:
Net unrealized gains/losses on securities			2.6		(0.8)
Available-for-sale securities, Income Tax:
Net unrealized gains/losses on securities			(0.9)		0.3
Available-for-sale securities, After-Tax Amount:
Net unrealized gains/losses on securities			$ 1.7		$ (0.5)

[1] Less than $0.1.

[2] See Deferred Policy Acquisition Costs and Value of Business Acquired Note to these Condensed Consolidated Financial Statements for additional information.

[3] See Derivative Financial Instruments Note to these Condensed Consolidated Financial Statements for additional information.

[4] Amount reported in Net periodic pension cost which is reported in Operating expenses.See Benefit Plans Note in the Company's 2012 Annual Report on Form 10-K for additional information.

[5] Amount includes $30.5 valuation allowance. See Income Taxes Note to these Condensed Consolidated Financial Statements for additional information.