Fair Value (Significant Unobservable Inputs Used in Level 3 Valuations of Assets and Liabilities) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2015		Dec. 31, 2014		Mar. 31, 2014	Dec. 31, 2013
Fair Value Measurement Inputs Disclosure [Line Items]
Fair Value Assets	$ 105.2		$ 102.6		$ 129.5	$ 131.8
Fair Value Liabilities	79.0
S and P Five Hundred Index Options [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Fair Value Assets	13.0		13.6		15.4	15.8
FairValueMeasurementsSignificantAssumptions	Various assumptions		Various assumptions
FairValueMeasurementsValuationTechniques	Black-Scholes option pricing model		Black-Scholes option pricing model
S and P Five Hundred Index Options [Member] | Various Assumptions [Member] | Black-Scholes Option Pricing model [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Unobservable Inputs	(a)	[1]	(a)	[1]
Index Based Interest Guarantees [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Fair Value Liabilities	79.0		77.0		69.8	67.6
Unobservable Inputs	Expected future option, Various assumptions		Expected future option, Various assumptions
FairValueMeasurementsValuationTechniques	Discounted cash , Black-Scholes option pricing model		Discounted cash , Black-Scholes option pricing model
Index Based Interest Guarantees [Member] | Various Assumptions [Member] | Black-Scholes Option Pricing model [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Fair Value Liabilities	79.0
Unobservable Inputs	(a)	[1]	(a)	[1]
Index Based Interest Guarantees [Member] | Various Assumptions [Member] | Discounted Cash flow [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Unobservable Inputs	(b)	[2]	(b)	[2]
Index Based Interest Guarantees [Member] | Various Assumptions [Member] | Discounted Cash flow [Member] | Maximum [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Unobservable Inputs	36%		36%
Index Based Interest Guarantees [Member] | Various Assumptions [Member] | Discounted Cash flow [Member] | Minimum [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Unobservable Inputs	5%		5%
Index Based Interest Guarantees [Member] | Expected Future Option Purchase [Member] | Discounted Cash flow [Member] | Maximum [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Unobservable Inputs	3%		3%
Index Based Interest Guarantees [Member] | Expected Future Option Purchase [Member] | Discounted Cash flow [Member] | Minimum [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Unobservable Inputs	1%		1%
Commercial Mortgage Loans [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Fair Value Assets	54.9		56.0
Unobservable Inputs	Reduction on appraisal , Capitalization rate (c)	[3]	Reduction on appraisal , Capitalization rate (c)	[3]
FairValueMeasurementsValuationTechniques	Appraisals, Cash flows		Appraisals, Cash flows
Commercial Mortgage Loans [Member] | Reduction On Appraisal [Member] | Appraisals [Member] | Maximum [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Unobservable Inputs	37%		37%
Commercial Mortgage Loans [Member] | Reduction On Appraisal [Member] | Appraisals [Member] | Minimum [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Unobservable Inputs	0%		0%
Commercial Mortgage Loans [Member] | Capitalization Rate [Member] | Cash Flows [Member] | Maximum [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Unobservable Inputs	16%		16%
Commercial Mortgage Loans [Member] | Capitalization Rate [Member] | Cash Flows [Member] | Minimum [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Unobservable Inputs	7%		7%
Real Estate Owned [Member] | Reduction On Appraisal [Member] | Appraisals [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Fair Value Assets	$ 3.1		$ 10.3
Real Estate Owned [Member] | Reduction On Appraisal [Member] | Appraisals [Member] | Maximum [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Unobservable Inputs	11%		11%
Real Estate Owned [Member] | Reduction On Appraisal [Member] | Appraisals [Member] | Minimum [Member]
Fair Value Measurement Inputs Disclosure [Line Items]
Unobservable Inputs	0%		0%

[1] Represents various assumptions derived from market data, which include estimates of bid ask spreads and the implied volatilities for the S&P 500 index.

[2] Represents various actuarial assumptions which include combined lapse, mortality and withdrawal decrement rates which generally have a range of inputs from 5%-36%.

[3] Capitalization rates are used as an internal analysis in converting the underlying property's income to an estimated property value.