Earnings Per Share (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of the components of basic and diluted shares in the EPS Calculation [Abstract]
Weighted-average basic common shares outstanding	175,400,000	176,500,000	177,400,000
Potential number of shares issuable under the Company's LTSIP	600,000	1,000,000	1,400,000
Weighted-average diluted common shares outstanding	176,000,000	177,500,000	178,800,000
Dividend Reinvestment and Stock Purchase Plan (Reinvestment Plan) [Abstract]
Shares issued	0	0	4,400
Shares reserved for future issuance	20,210,415
Stock Options [Member]
Long-Term Stock Incentive Plan [Abstract]
Stock option minimum term (in years)	5 years
Stock option maximum term (in years)	10 years
Stock option majority minimum term (in years)	7 years
Stock option majority maximum term (in years)	10 years
Minimum number of installments for vesting of options held by employees	3
Maximum number of installments for vesting of options held by employees	4
Restricted Shares [Member]
Long-Term Stock Incentive Plan [Abstract]
Vesting period for share-based award (in years)	3 years
Performance Shares [Member]
Long-Term Stock Incentive Plan [Abstract]
Performance share performance period (in years)	3 years