Earnings Per Share (Calculation Of Earnings Per Share) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net Income Attributable to Common Shareholders	$ 153.9	$ 183.0	$ 347.8	$ 360.5
Basic Earnings Per Share [Member]
Net Income Attributable to Common Shareholders	153.9	183.0	347.8	360.5
Weighted Average Number of Shares	453.8	465.5	454.0	467.7
Per Share Amount	$ 0.34	$ 0.39	$ 0.77	$ 0.77
Dilutive Effect Of Share-Based Awards [Member]
Net Income Attributable to Common Shareholders	0	0	0	0
Weighted Average Number of Shares	1.5	1.9	1.6	2.0
Per Share Amount	$ 0	$ 0	$ 0	$ 0
Diluted Earnings Per Share [Member]
Net Income Attributable to Common Shareholders	$ 153.9	$ 183.0	$ 347.8	$ 360.5
Weighted Average Number of Shares	455.3	467.4	455.6	469.7
Per Share Amount	$ 0.34	$ 0.39	$ 0.76	$ 0.77