Share-Based Compensation Plans (Stock Option Activity) (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years		Dec. 31, 2010	Dec. 31, 2009
Share-Based Compensation Plans [Abstract]
Options, Outstanding at beginning of year	11,052
Weighted- Average Exercise Price, Outstanding at beginning of year	$ 21.70
Exercised Options	(2,449)	[1]
Exercised, Weighted- Average Exercise Price	$ 10.77	[1]
Canceled Options	(30)
Canceled, Weighted- Average Exercise Price	$ 16.66
Expired, Options	(1,627)
Expired, Weighted- Average Exercise Price	$ 29.30
Options, Outstanding at end of year	6,946		11,052
Weighted- Average Exercise Price, Outstanding at end of year	$ 23.80		$ 21.70
Weighted- Average Remaining Contractual Life , Outstanding at end of year, in years	3.2
Exercisable at end of period, Option	6,372
Exercisable at end of period, Weighted- Average Exercise Price	$ 24.68
Weighted- Average Remaining Contractual Life , Exercisable at end of period, in years	3.0
Aggregate Intrinsic Value , Exercisable at end of period	$ 19
Aggregate intrinsic value of shares exercised	$ 33		$ 42	$ 1

[1] The aggregate intrinsic value of shares exercised in 2011, 2010 and 2009 was $33 million, $42 million and less than $1 million, respectively.