CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2011	Dec. 31, 2010
Capitalization
Preferred stock, shares authorized (in shares)	7,000,000	7,000,000
Preferred stock, par value per share (in dollars per share)	$ 100	$ 100
Preferred stock, shares outstanding (in shares)	0	1,049,800
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, par value (in dollars per share)	$ 2.50	$ 2.50
Common stock, shares outstanding (in shares)	486,493,933	482,333,750