Consolidated Balance Sheets Parentheticals (USD $) In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 100	$ 100
Common stock, par value	$ 0.01	$ 0.01
Common stock, authorized shares	600.0	600.0
Common stock, issued shares	277.3	320.0
Common stock, outstanding shares	276.1	318.8