Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 30,676	$ 19,180
Allowance for depreciation, property, plant and equipment	$ 814,710	$ 759,640
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	450,000,000	450,000,000
Common stock, shares issued	154,357,198	154,841,438