Investments (Tables)

3 Months Ended

Mar. 31, 2013

Notes to Financial Statements [Abstract]

Schedule of Available-for-sale Securities Reconciliation

At March 31, 2013 and December 31, 2012, all fixed maturity securities were classified as available-for-sale. The amortized cost and fair values of securities by security type are shown as follows.

	March 31, 2013
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss		Fair Value
	(in millions of dollars)
United States Government and Government Agencies and Authorities	$	1,027.3	$	309.2	$	1.4	$	1,335.1
States, Municipalities, and Political Subdivisions	1,550.8		308.5		5.5		1,853.8
Foreign Governments	1,197.3		260.5		—		1,457.8
Public Utilities	9,316.7		1,782.4		9.9		11,089.2
Mortgage/Asset-Backed Securities	1,767.1		275.6		0.5		2,042.2
All Other Corporate Bonds	22,740.4		3,907.7		29.0		26,619.1
Redeemable Preferred Stocks	33.0		6.3		—		39.3
Total Fixed Maturity Securities	$	37,632.6	$	6,850.2	$	46.3	$	44,436.5

	December 31, 2012
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss		Fair Value
	(in millions of dollars)
United States Government and Government Agencies and Authorities	$	1,020.9	$	329.0	$	1.1	$	1,348.8
States, Municipalities, and Political Subdivisions	1,498.4		316.2		7.8		1,806.8
Foreign Governments	1,280.4		226.6		—		1,507.0
Public Utilities	9,294.3		1,865.0		15.1		11,144.2
Mortgage/Asset-Backed Securities	1,927.9		289.1		0.5		2,216.5
All Other Corporate Bonds	22,696.6		4,245.3		31.5		26,910.4
Redeemable Preferred Stocks	33.0		6.3		—		39.3
Total Fixed Maturity Securities	$	37,751.5	$	7,277.5	$	56.0	$	44,973.0

As of March 31, 2013 and December 31, 2012, we held no fixed maturity securities for which a portion of an other-than-temporary impairment had previously been recognized in other comprehensive income.

Length of Time Fixed Maturity Securities had been in a Gross Unrealized Loss Position

The following charts indicate the length of time our fixed maturity securities have been in a gross unrealized loss position.

	March 31, 2013
	Less Than 12 Months				12 Months or Greater
	Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss
	(in millions of dollars)
United States Government and Government Agencies and Authorities	$	—	$	—	$	6.2	$	1.4
States, Municipalities, and Political Subdivisions	91.0		1.8		45.3		3.7
Public Utilities	224.4		4.1		57.4		5.8
Mortgage/Asset-Backed Securities	2.5		—		3.8		0.5
All Other Corporate Bonds	843.4		14.9		323.8		14.1
Total Fixed Maturity Securities	$	1,161.3	$	20.8	$	436.5	$	25.5

	December 31, 2012
	Less Than 12 Months				12 Months or Greater
	Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss
	(in millions of dollars)
United States Government and Government Agencies and Authorities	$	—	$	—	$	6.5	$	1.1
States, Municipalities, and Political Subdivisions	30.8		0.9		42.1		6.9
Public Utilities	110.3		3.9		147.6		11.2
Mortgage/Asset-Backed Securities	4.4		—		3.8		0.5
All Other Corporate Bonds	441.3		7.0		396.8		24.5
Total Fixed Maturity Securities	$	586.8	$	11.8	$	596.8	$	44.2

Distribution of the Maturity Dates for Fixed Maturity Securities

The following is a distribution of the maturity dates for fixed maturity securities. The maturity dates have not been adjusted for possible calls or prepayments.

	March 31, 2013
	Total Amortized Cost		Unrealized Gain Position				Unrealized Loss Position
			Gross Gain		Fair Value		Gross Loss		Fair Value
	(in millions of dollars)
1 year or less	$	1,059.7	$	23.6	$	1,040.1	$	0.2	$	43.0
Over 1 year through 5 years	5,927.8		654.8		6,501.5		1.7		79.4
Over 5 years through 10 years	9,756.5		1,548.7		10,799.5		8.0		497.7
Over 10 years	19,121.5		4,347.5		22,461.7		35.9		971.4
	35,865.5		6,574.6		40,802.8		45.8		1,591.5
Mortgage/Asset-Backed Securities	1,767.1		275.6		2,035.9		0.5		6.3
Total Fixed Maturity Securities	$	37,632.6	$	6,850.2	$	42,838.7	$	46.3	$	1,597.8

	December 31, 2012
	Total Amortized Cost		Unrealized Gain Position				Unrealized Loss Position
			Gross Gain		Fair Value		Gross Loss		Fair Value
	(in millions of dollars)
1 year or less	$	956.4	$	21.2	$	934.1	$	0.5	$	43.0
Over 1 year through 5 years	5,922.8		628.1		6,449.8		5.0		96.1
Over 5 years through 10 years	9,752.3		1,606.4		10,997.0		7.6		354.1
Over 10 years	19,192.1		4,732.7		23,200.2		42.4		682.2
	35,823.6		6,988.4		41,581.1		55.5		1,175.4
Mortgage/Asset-Backed Securities	1,927.9		289.1		2,208.3		0.5		8.2
Total Fixed Maturity Securities	$	37,751.5	$	7,277.5	$	43,789.4	$	56.0	$	1,183.6

Mortgage Loans by Property Type

Mortgage loans by property type and geographic region are as follows:

	March 31, 2013				December 31, 2012
	(in millions of dollars)
	Carrying		Percent of		Carrying		Percent of
	Amount		Total		Amount		Total
Property Type
Apartment	$	33.8	2.0	%	$	34.0	2.0	%
Industrial	518.0		29.9		513.4		30.0
Mixed	77.8		4.5		78.4		4.6
Office	730.6		42.2		713.4		41.6
Retail	370.2		21.4		373.5		21.8
Total	$	1,730.4	100.0	%	$	1,712.7	100.0	%

Mortgage Loans by Geographic Region

Region
New England	$	113.2	6.5	%	$	114.3	6.7	%
Mid-Atlantic	158.9		9.2		160.0		9.3
East North Central	233.1		13.5		224.7		13.1
West North Central	158.0		9.1		160.8		9.4
South Atlantic	437.8		25.3		440.9		25.7
East South Central	79.1		4.6		79.6		4.7
West South Central	157.8		9.1		159.5		9.3
Mountain	89.6		5.2		90.5		5.3
Pacific	302.9		17.5		282.4		16.5
Total	$	1,730.4	100.0	%	$	1,712.7	100.0	%

Mortgage Loans, Sorted by Applicable Credit Quality Indicators, Internal Rating

Mortgage loans, sorted by the applicable credit quality indicators, are as follows:

	March 31 2013		December 31 2012
	(in millions of dollars)
Internal Rating
Aa	$	11.3	$	11.5
A	660.8		659.4
Baa	1,005.6		994.5
Ba	39.6		34.2
B	13.1		13.1
Total	$	1,730.4	$	1,712.7

Mortgage Loans, Sorted by Applicable Credit Quality Indicators, Loan to Value Ratio

Loan-to-Value Ratio
<= 65%	$	657.8	$	624.7
> 65% <= 75%	847.3		858.8
> 75% <= 85%	131.5		142.5
> 85%	93.8		86.7
Total	$	1,730.4	$	1,712.7

Activity in the Allowance for Credit Losses

The activity in the allowance for credit losses is as follows:

	Three Months Ended March 31
	2013		2012
	(in millions of dollars)
Balance at Beginning of Year	$	1.5	$	1.5
Provision	—		0.5
Balance at End of Period	$	1.5	$	2.0

Impaired Mortgage Loans

Impaired mortgage loans are as follows:

	March 31, 2013
	(in millions of dollars)
			Unpaid
	Recorded		Principal		Related
	Investment		Balance		Allowance
With No Related Allowance Recorded	$	4.3	$	4.3	$	—
With an Allowance Recorded	13.1		14.6		1.5
Total	$	17.4	$	18.9	$	1.5
	December 31, 2012
	(in millions of dollars)
			Unpaid
	Recorded		Principal		Related
	Investment		Balance		Allowance
With No Related Allowance Recorded	$	4.3	$	4.3	$	—
With an Allowance Recorded	13.1		14.6		1.5
Total	$	17.4	$	18.9	$	1.5

Schedule of Financial Instrument and Derivative Offsetting [Table Text Block]

Shown below are our financial instruments that either meet the accounting requirements that allow them to be offset in our balance sheets or that are subject to an enforceable master netting arrangement or similar agreement. Our accounting policy is to not offset these financial instruments in our balance sheets. Net amounts disclosed below have been reduced by the amount of collateral pledged to or received from our counterparties.

	Offsetting of Financial Assets and Derivative Assets
	March 31, 2013
	Gross				Net Amount of		Gross Amount Not
	Amount of		Gross Amount		Assets		Offset in Balance Sheet
	Recognized		Offset in		Presented in		Financial			Cash Collateral
	Assets		Balance Sheet		Balance Sheet		Instruments			Received			Net Amount
	(in millions of dollars)
Derivatives	$	62.1	$	—	$	62.1	$	(53.6	)	$	—		$	8.5
Securities Lending	234.0		—		234.0		—			(234.0		)	—
Total	$	296.1	$	—	$	296.1	$	(53.6	)	$	(234.0	)	$	8.5
	Offsetting of Financial Liabilities and Derivative Liabilities
	March 31, 2013
	Gross				Net Amount of		Gross Amount Not
	Amount of		Gross Amount		Liabilities		Offset in Balance Sheet
	Recognized		Offset in		Presented in		Financial			Cash Collateral
	Liabilities		Balance Sheet		Balance Sheet		Instruments			Pledged			Net Amount
	(in millions of dollars)
Derivatives	$	157.4	$	—	$	157.4	$	(117.7	)	$	(1.8	)	$	37.9
Securities Lending	236.3		—		236.3		(234.0		)	—			2.3
Total	$	393.7	$	—	$	393.7	$	(351.7	)	$	(1.8	)	$	40.2

	Offsetting of Financial Assets and Derivative Assets
	December 31, 2012
	Gross				Net Amount of		Gross Amount Not
	Amount of		Gross Amount		Assets		Offset in Balance Sheet
	Recognized		Offset in		Presented in		Financial			Cash Collateral
	Assets		Balance Sheet		Balance Sheet		Instruments			Received			Net Amount
	(in millions of dollars)
Derivatives	$	81.6	$	—	$	81.6	$	(72.9	)	$	—		$	8.7
Securities Lending	452.8		—		452.8		—			(452.8		)	—
Total	$	534.4	$	—	$	534.4	$	(72.9	)	$	(452.8	)	$	8.7
	Offsetting of Financial Liabilities and Derivative Liabilities
	December 31, 2012
	Gross				Net Amount of		Gross Amount Not
	Amount of		Gross Amount		Liabilities		Offset in Balance Sheet
	Recognized		Offset in		Presented in		Financial			Cash Collateral
	Liabilities		Balance Sheet		Balance Sheet		Instruments			Pledged			Net Amount
	(in millions of dollars)
Derivatives	$	170.5	$	—	$	170.5	$	(129.8	)	$	(1.8	)	$	38.9
Securities Lending	455.8		—		455.8		(452.8		)	—			3.0
Total	$	626.3	$	—	$	626.3	$	(582.6	)	$	(1.8	)	$	41.9

Investment Income [Table Text Block]

Net Investment Income

Net investment income reported in our consolidated statements of income is as follows:

	Three Months Ended March 31
	2013		2012
	(in millions of dollars)
Fixed Maturity Securities	$	589.9	$	595.5
Derivative Financial Instruments	7.7		6.3
Mortgage Loans	26.0		25.0
Policy Loans	3.7		3.6
Other Long-term Investments	7.7		3.2
Short-term Investments	0.8		1.2
Gross Investment Income	635.8		634.8
Less Investment Expenses	7.1		7.2
Less Investment Income on PFA Assets	4.0		4.1
Less Amortization of Tax Credit Partnerships	3.6		4.0
Net Investment Income	$	621.1	$	619.5

Realized Investment Gains and Losses Reported in Consolidated Statements of Income

Realized Investment Gain and Loss

Realized investment gains and losses reported in our consolidated statements of income are as follows:

	Three Months Ended March 31
	2013			2012
	(in millions of dollars)
Fixed Maturity Securities
Gross Gains on Sales	$	6.6		$	5.9
Gross Losses on Sales	(5.5		)	(5.0		)
Other-Than-Temporary Impairment Loss	(0.8		)	—
Mortgage Loans and Other Invested Assets
Gross Gains on Sales	7.6			—
Impairment Loss	(1.0		)	(0.5		)
Embedded Derivative in Modified Coinsurance Arrangement	6.4			12.3
Other Derivatives	(0.3		)	—
Foreign Currency Transactions	(2.7		)	(0.3		)
Net Realized Investment Gain	$	10.3		$	12.4