Consolidated Balance Sheet (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015	[1]
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.625	$ 0.625
Common stock, shares authorized	860,000,000	860,000,000
Common stock, shares issued	412,612,102	411,218,105
Treasury stock, shares	33,172,426	33,183,930

[1] Financial information for 2015 has been recast to reflect retrospective application of the successful efforts method of accounting. See Note 1.