Shareholders' Equity Shareholders' Equity (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share Repurchases Authorized per Capital Plan	236
Share Repurchases Remaining per Capital Plan	59
Stock Option
Common stock shares reserved for future issuance	14,700,000
Restricted Stock
Shares of non-vested restricted stock outstanding	2,140,000	2,479,000
Common Stock
Shares repurchased under share repurchase program	5,400,000	7,500,000	10,200,000
Warrants
Number of warrants to purchase common stock outstanding	13,200,000
Number of shares of common stock issuable under outstanding warrants	11,200,000
Average exercise price for outstanding warrants	29.45
Shares of common stock issued upon exercise of warrants	361,000	0	0
Common stock shares reserved for future issuance	11,200,000
Share Repurchase Program | Common Stock
Shares repurchased under share repurchase program	5,200,000	7,400,000	10,100,000
Average cost per share of shares repurchased under share repurchase program	47.91	38.63	30.21