Shareholders’ Equity - Dividends (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Mar. 31, 2016
Shareholders’ Equity
Dividends declared per common share (in dollars per share)	$ 0.16	$ 0.16	$ 0.14	$ 0.14
Dividends paid	$ 49.3			$ 43.2
Dividends declared	$ 48.9			$ 43.0

Aggregate dividends declared during the period for each share of common stock outstanding.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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Amount of paid and unpaid common stock dividends declared with the form of settlement in cash.

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Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3291-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

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