Benefit Plans (Stock Option and SARs Activity) (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Stock options and Stock appreciation rights awards outstanding at January 1	1,625,175
Weighted-average exercise price per award outstanding at January 1	$ 27.42
Number of awards granted	125,000
Weighted-average exercise price on awards granted	$ 27.12
Number of awards exercised	(166,375)
Weighted-average exercise price on awards exercised	$ 27.13
Number of awards forfeited, canceled or expired	(264,450)
Weighted-average exercise price on awards forfeited, canceled or expired	$ 34.51
Stock options and Stock appreciation rights awards outstanding at December 31	1,319,350
Weighted-average exercise price per award outstanding at December 31	$ 26.01
Aggregate intrinsic value on awards outstanding	$ 5
Weighted-average remaining contractual term on awards outstanding	5.80
Number of awards outstanding, fully vested and expected to vest	1,260,045
Weighted-average exercise price per award outstanding, fully vested and expected to vest	$ 26.14
Aggregate intrinsic value on awards outstanding, fully vested and expected to vest	5
Weighted-average remaining contractual term on awards outstanding, fully vested and expected to vest	5.69
Number of awards outstanding, exercisable	872,600
Weighted-average exercise price, awards outstanding, exercisable	$ 28.04
Aggregate intrinsic value, awards outstanding, exercisable	$ 2
Weighted-average remaining contractual term, awards outstanding, exercisable	4.79