Retirement Benefits - Summary of Components of Retirement Benefit Expense (Income) (Footnote) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
Dec. 31, 2015	Dec. 31, 2016	Nov. 30, 2015	Nov. 30, 2014
Compensation and Retirement Disclosure [Abstract]
Actual gain (loss) on assets	$ (22.2)	$ 93.7	$ (64.2)	$ 63.5
Actual rate of return on assets	(2.30%)	10.80%	(6.10%)	5.10%

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