Shareholders' Equity (Summary of Changes in Amounts of Stock Options Outstanding) (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2011	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding and exercisable beginning, Shares	628
Exercised, Shares	(622)		(1,174)
Forfeited/expired, Shares	(6)		(8)
Outstanding and exercisable ending, Shares	0	1,810
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding and exercisable beginning, Weighted-average Exercise Price	$ 30.81
Exercised, Weighted-average Exercise Price	$ 30.79	$ 32.46
Forfeited/expired, Weighted-average Exercise Price	$ 32.26	$ 31.57
Outstanding and exercisable ending, Weighted-average Exercise Price	$ 0.00	$ 31.76
Outstanding and exercisable beginning, Aggregated Intrinsic Value	$ 14
Exercised, Aggregated Intrinsic Value	13		17
Outstanding and exercisable ending, Aggregated Intrinsic Value	$ 0	$ 20