Earnings Per Share (EPS) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended	1 Months Ended
Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Apr. 30, 2012 Exchangeable Senior Notes [Member]
Weighted-average number of basic shares	291.6	307.7	295.9	305.4
Shares issuable under incentive stock plans	3.9	4.3	3.9	3.5
Exchangeable Senior Notes	0	0	0	4.0
Weighted average number of diluted shares	295.5	312.0	299.8	312.9
Anti-dilutive shares	1.0	2.6	1.1	5.8
Settlement of Exchangeable Senior Notes				$ (4.5)	$ 357.0
Shares issued for settlement of Exchangeable Senior Notes, in millions, shares					10.8

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible debt securities using the if-converted method.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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