Stockholders' Equity (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract]
Preferred stock, shares authorized	100,000	100,000
Preferred stock, par value per share	$ 100	$ 100
Common stock, shares authorized	500,000,000	500,000,000
Common stock, par value per share	$ 1	$ 1
Common stock, shares issued	254,119,478	250,591,610
Number of treasury shares held	79,401,585	67,000,487
Share Repurchases [Line Items]
Shares repurchased	12,401,098	4,115,139	2,417,955
Average price per share for repurchased shares (in dollars per share)	$ 60.38	$ 58.93	$ 51.10
May 2012 Authorization [Member]
Share Repurchases [Line Items]
Number of shares authorized to be repurchased	10,000,000
Shares repurchased	6,091,711
Remaining number of shares authorized to be repurchased	3,908,289
November 2012 Authorization [Member]
Share Repurchases [Line Items]
Authorized dollar amount for share repurchase program	$ 1,000,000,000
Shares repurchased	3,963,084
Remaining dollar amount authorized to be repurchased	$ 749,898,000
Shares repurchased in open market [Member]
Share Repurchases [Line Items]
Shares repurchased	12,314,795	4,034,973	2,335,500
Shares repurchased from holders of employee stock options [Member]
Share Repurchases [Line Items]
Shares repurchased	86,303	80,166	82,455