Retirement Benefits (Details 12) - Pension Benefits [Member] - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	$ 1,962.3	$ 2,204.4
Net Realized and Unrealized Gains (Losses)	79.7	(41.1)
Fair value of plan assets at end of year	1,894.6	1,962.3
Fixed income and cash equivalents [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	369.7
Fair value of plan assets at end of year	412.2	369.7
Floating rate [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	358.0
Fair value of plan assets at end of year	164.0	358.0
Private equity [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	201.2
Fair value of plan assets at end of year	204.1	201.2
Hedge funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	51.9
Fair value of plan assets at end of year	283.9	51.9
Real estate and other [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	186.5
Fair value of plan assets at end of year	96.5	186.5
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	305.6	361.3
Net Realized and Unrealized Gains (Losses)	12.1	4.4
Net Purchases, Issuances and Settlements	(218.4)	(60.1)
Net Transfers Into (Out Of) Level 3	0.0	0.0
Fair value of plan assets at end of year	99.3	305.6
Significant Unobservable Inputs (Level 3) [Member] \| Fixed income and cash equivalents [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0.3	0.3
Net Realized and Unrealized Gains (Losses)	0.0	0.0
Net Purchases, Issuances and Settlements	(0.1)	0.0
Net Transfers Into (Out Of) Level 3	0.0	0.0
Fair value of plan assets at end of year	0.2	0.3
Significant Unobservable Inputs (Level 3) [Member] \| Floating rate [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	305.3	361.0
Net Realized and Unrealized Gains (Losses)	12.1	4.4
Net Purchases, Issuances and Settlements	(218.3)	(60.1)
Net Transfers Into (Out Of) Level 3	0.0	0.0
Fair value of plan assets at end of year	99.1	305.3
Significant Unobservable Inputs (Level 3) [Member] \| Private equity [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
Significant Unobservable Inputs (Level 3) [Member] \| Hedge funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	0.0	0.0
Significant Unobservable Inputs (Level 3) [Member] \| Real estate and other [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0.0
Fair value of plan assets at end of year	$ 0.0	$ 0.0

The difference between fair value of plan assets at the end of the period and the fair value at the beginning of the period, adjusted for contributions and payments of benefits during the period, and after adjusting for taxes and other expenses, as applicable.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Actual Return on Plan Assets (Component of Net Periodic Postretirement Benefit Cost)
-URI http://asc.fasb.org/extlink&oid=6504192

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Actual Return on Plan Assets (Component of Net Periodic Pension Cost)
-URI http://asc.fasb.org/extlink&oid=6504226

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