SCHEDULE V VALUATION AND QUALIFYING ACCOUNTS (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reinsurance recoverable on paid losses: Allowance for reinsurance balances
VALUATION AND QUALIFYING ACCOUNTS
Balance at beginning of period	$ 23.7	$ 35.5	$ 34.4
Charged to costs and expenses	(1.1)	(0.6)	(0.6)
Charged to other accounts	0	0	0
Deductions described	(11.2)	(11.2)	1.7
Balance at end of period	11.4	23.7	35.5
Property and casualty insurance and reinsurance premiums receivable: Allowance for uncollectible accounts
VALUATION AND QUALIFYING ACCOUNTS
Balance at beginning of period	4.0	4.4	3.4
Charged to costs and expenses	(0.2)	1.0	1.1
Charged to other accounts	(1.0)	0	0
Deductions described	0.1	(1.4)	(0.1)
Balance at end of period	2.9	4.0	4.4
Allowance for Doubtful Accounts [Member]
VALUATION AND QUALIFYING ACCOUNTS
Balance at beginning of period	0
Charged to costs and expenses	3.6
Charged to other accounts	0
Deductions described	(0.3)
Balance at end of period	$ 3.3

Name:	us-gaap_MovementInValuationAllowancesAndReservesRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 09

-Article 12

+ Details

Name:	us-gaap_ValuationAllowancesAndReservesBalance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

+ References

+ Details

Name:	us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

+ References

+ Details

Name:	us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Total of the deductions in a given period to allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, representing receivables written off as uncollectible and portions of the reserves utilized, respectively.

+ References

+ Details

Name:	us-gaap_ValuationAllowancesAndReservesDeductions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_ValuationAllowancesAndReservesTypeAxis=us-gaap_AllowanceForDoubtfulAccountsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationAllowancesAndReservesTypeAxis=us-gaap_AllowanceForReinsuranceRecoverableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationAllowancesAndReservesTypeAxis=us-gaap_AllowanceForUncollectiblePremiumsReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: