Earnings per Common Share (Details) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Earnings per Common Share
Weighted-average shares - basic	420,188	419,075	416,996
Dilution effect of stock options, stock appreciation rights and stock awards at end of period (in shares)	2,187	2,912	4,526
Weighted-average shares - diluted	422,375	421,987	421,522
Weighted-average stock awards and shares excluded from diluted earnings per share due to the anti-dilutive effect	5	85	5