Earnings per Common Share (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Weighted-average shares - basic	413,713	417,291	413,530	417,097
Dilution effect of stock appreciation rights and stock awards at end of period (in shares)	0	1,801	1,348	1,645
Weighted-average shares - diluted	413,713	419,092	414,878	418,742
Weighted-average stock awards and shares excluded from diluted EPS due to the anti-dilutive effect	1,655	2	400	409