Consolidated Statement of Equity (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Common stock, dividends declared	$ 1.69	$ 1.56	$ 1.52
Mandatory Convertible [Member]
Dividend on mandatory convertible preferred stock			6.00%