Earnings Per Share (Calculation Of Earnings Per Share) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net Income Attributable to Common Shareholders	$ 170.6	$ 166.9	$ 518.4	$ 527.4
Basic Earnings Per Share [Member]
Net Income Attributable to Common Shareholders	170.6	166.9	518.4	527.4
Weighted Average Number of Shares	451.3	459.5	453.1	464.9
Per Share Amount	$ 0.38	$ 0.36	$ 1.14	$ 1.13
Dilutive Effect Of Share-Based Awards [Member]
Net Income Attributable to Common Shareholders	0	0	0	0
Weighted Average Number of Shares	1.5	1.5	1.5	1.9
Per Share Amount	$ 0	$ 0	$ 0	$ 0
Diluted Earnings Per Share [Member]
Net Income Attributable to Common Shareholders	$ 170.6	$ 166.9	$ 518.4	$ 527.4
Weighted Average Number of Shares	452.8	461.0	454.6	466.8
Per Share Amount	$ 0.38	$ 0.36	$ 1.14	$ 1.13