Segments (Operating Earnings Before Income Taxes) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]
Total operating earnings before income taxes	$ 231.1	$ 256.7
Closed Block Variable Annuity	20.2	(477.1)
Net investment gains (losses) and related charges and adjustments	57.6	41.8
Net guaranteed benefit hedging gains (losses) and related charges and adjustments	6.4	3.1
Loss related to businesses exited through reinsurance or divestment	(10.5)	(16.9)
Income (loss) attributable to noncontrolling interests	13.5	(13.5)
Other adjustments to operating income	(16.0)	(8.4)
Income (loss) before income taxes	302.3	(214.3)
Retirement Solutions \| Retirement
Segment Reporting Information [Line Items]
Total operating earnings before income taxes	114.9	137.8
Retirement Solutions \| Annuities
Segment Reporting Information [Line Items]
Total operating earnings before income taxes	54.8	54.3
Investment Management
Segment Reporting Information [Line Items]
Total operating earnings before income taxes	49.8	30.1
Insurance Solutions \| Individual Life
Segment Reporting Information [Line Items]
Total operating earnings before income taxes	31.1	50.8
Insurance Solutions \| Employee Benefits
Segment Reporting Information [Line Items]
Total operating earnings before income taxes	16.9	12.4
Total Ongoing Businesses
Segment Reporting Information [Line Items]
Total operating earnings before income taxes	267.5	285.4
Corporate
Segment Reporting Information [Line Items]
Total operating earnings before income taxes	(37.3)	(50.1)
Closed Blocks
Segment Reporting Information [Line Items]
Total operating earnings before income taxes	0.9	21.4
Closed Blocks \| Closed Block Institutional Spread Products
Segment Reporting Information [Line Items]
Total operating earnings before income taxes	5.4	22.1
Closed Blocks \| Closed Block Other
Segment Reporting Information [Line Items]
Total operating earnings before income taxes	$ (4.5)	$ (0.7)

Interest and Dividend Income (Loss), Securities, Closed Block Variable Annuity

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- Definition

Other Adjustments to Operating Income (Loss)

+ References

No definition available.

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- Definition

Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5618551-113959

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- Definition

This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains (losses) realized during the period from the sale of investments accounted for under the cost method of accounting and losses recognized for other than temporary impairments (OTTI) of the subject investments.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.7(c),9(a))

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (c)

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Article 5

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 9

-Subparagraph (c)-(e)

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- Definition

Gain (loss) from sale or disposal of an organization or integrated set of activities (for example, but not limited to, a partnership or corporation) engaged in providing a product or service in a commercial, industrial, or professional environment.

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No definition available.

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- Definition

This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 10

-Article 5

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- Definition

Sum of operating profit and nonoperating income or expense before Income or Loss from equity method investments, income taxes, extraordinary items, and noncontrolling interest.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(h)(1)(i))

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- Definition

Amount of Net Income (Loss) attributable to noncontrolling interest.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 1A

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-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 55

-Paragraph 4J

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