Employee Benefit Plans - Assumed Health Care Cost Trend Rates (Details) (Other Post-retirement Benefits, USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other Post-retirement Benefits
Effect of one-percentage point change in assumed health care cost trend rates [Abstract]
Effect of one percentage point increase on total of service and interest cost components	$ 0.1	$ 0	$ 0
Effect of one percentage point increase on post-retirement benefit obligation	1.1	1.2	0.6
Effect of one percentage point decrease on total of service and interest cost components	(0.1)	0	0
Effect of one percentage point decrease on post-retirement benefit obligation	$ (0.9)	$ (1.0)	$ (0.5)

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Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (m)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

+ Details

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- Definition

Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

+ References

+ Details

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- Definition

The effect of a one-percentage-point increase in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

+ References

+ Details

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- Definition

The effect of a one-percentage-point increase in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

+ References

+ Details

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