Share-Based Compensation (Movements Of Share Awards Priced In Pounds Sterling) (Details) In Millions, except Per Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2013 USD ($)	Sep. 30, 2013 Weighted Average Grant Date Fair Value (Sterling) [Member] GBP (£)	Sep. 30, 2012 Weighted Average Grant Date Fair Value (Sterling) [Member] GBP (£)	Sep. 30, 2013 Performance Shares [Member]	Sep. 30, 2012 Performance Shares [Member]	Sep. 30, 2013 Time-Vested [Member]	Sep. 30, 2012 Time-Vested [Member]
Unvested at the beginning of period				0.3	0	0.3	0.6
Vested and distributed during the period				(0.1)	0	(0.2)	(0.3)
Unvested at the end of the period				0.4	0.3	0.1	0.3
Unvested at the beginning of period, Weighted Average Grant Date Fair Value		£ 12.90	£ 11.25
Vested and distributed during the period, Weighted Average Grant Date Fair Value	$ 19.93	£ 12.90	£ 9.66
Unvested at the end of the period, Weighted Average Grant Date Fair Value		£ 12.90	£ 12.90