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Shareholders' Equity (Share Repurchase) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Feb. 08, 2016	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Class of Stock [Line Items]
Aggregate purchase price			$ 237.3	$ 487.7	$ 55.7
Stock Repurchase Program Board Authorized Repurchases [Member]
Class of Stock [Line Items]
Shares repurchased (in shares)			3.9	9.4	1.1
Aggregate purchase price			$ 235.1	$ 485.1	$ 53.5
Average purchase price per share (in dollars per share)			$ 60.49	$ 51.59	$ 47.37
Treasury Shares Retirement [Member]
Class of Stock [Line Items]
Treasury Stock, Shares, Retired		43.0
Stock Repurchase Program Board Authorized Repurchases [Member] | Stock Repurchase Program Board Authorized Repurchases [Member]
Class of Stock [Line Items]
Shares repurchased (in shares)	3.6
Aggregate purchase price	$ 160.3
Average purchase price per share (in dollars per share)	$ 44.79
Remaining amount available for share repurchase	$ 135.3

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Amount remaining of a stock repurchase plan authorized.

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Total cost of shares repurchased divided by the total number of shares repurchased.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

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Number of shares that have been repurchased during the period and are being held in treasury.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30
-Article 5

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Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

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-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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-Paragraph 1
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