Stockholder's Equity (Details) - shares	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Preferred Stock, $1.00 par value:
Authorized shares	50,000,000	50,000,000
Issued shares	25,875,000	25,875,000
Outstanding shares	25,875,000	25,875,000	26,108,236	26,224,854
Common Stock, $1.00 par value:
Authorized shares	700,000,000	700,000,000
Issued shares	355,594,373	329,487,615
Outstanding shares	354,777,670	328,790,066