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Contingencies (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended			6 Months Ended
	Jun. 30, 2007	Jun. 30, 2016	Sep. 30, 2015	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Oct. 07, 2011
Loss Contingencies [Line Items]
Net gain on sale of discontinued operations		$ 366.6		$ (0.1)	$ 366.6	$ 7.9
Esurance
Loss Contingencies [Line Items]
Percentage of fluctuation in loss reserves of transferred subsidiaries retained							90.00%
Tribune Company Litigation | Pending Litigation | OneBeacon [Member]
Loss Contingencies [Line Items]
Proceeds from Sale, Maturity and Collection of Investments	$ 32.0
Discontinued Operations [Member]
Loss Contingencies [Line Items]
Net gain on sale of discontinued operations		(8.0)		(0.4)	(6.9)	62.9
Esurance | Discontinued Operations [Member]
Loss Contingencies [Line Items]
Net gain on sale of discontinued operations			$ 10.3	(0.3)	28.3	7.6
OneBeacon Runoff [Member] | Discontinued Operations [Member]
Loss Contingencies [Line Items]
Net gain on sale of discontinued operations				0.3		0.3
Sirius Group
Loss Contingencies [Line Items]
Net gain on sale of discontinued operations					366.6
Sirius Group | Discontinued Operations [Member]
Loss Contingencies [Line Items]
Net gain on sale of discontinued operations		$ (3.4)		$ 3.8	$ (4.3)	$ 69.7

X

- Definition

Amount after tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=51717284&loc=d3e1361-107760

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 3B
-URI http://asc.fasb.org/extlink&oid=51716988&loc=SL51721525-107759

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-URI http://asc.fasb.org/extlink&oid=51717284&loc=SL51721675-107760

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=51716988&loc=d3e957-107759

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+ References

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Proceeds from Tribune common stock tendered in connecttion with Tribune's leveraged buyout.

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