Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Statement of Financial Position [Abstract]
First preferred shares, no par value
First preferred shares, shares issued	0	0
First preferred shares, shares outstanding	0	0
Common shares, no par value
Common shares, shares issued	259,015,970	258,669,486
Common shares, shares outstanding	259,015,970	258,669,486