Preferred and Common Stock - Schedule of Share Activity (Detail)					12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2012 Outstanding Stock [Member]	Dec. 31, 2011 Outstanding Stock [Member]	Dec. 31, 2010 Outstanding Stock [Member]	Dec. 31, 2012 Treasury Stock [Member]	Dec. 31, 2011 Treasury Stock [Member]	Dec. 31, 2010 Treasury Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Treasury stock, beginning balance	110,694,604	113,494,491	119,362,029	122,695,718
Private placement						36,518,563	44,313,146
Conversion of convertible notes							310
Issued for stock-based compensation plans					2,799,887	5,867,538	3,333,689	(2,799,887)	(5,867,538)	(3,333,689)
Treasury stock, ending balance	110,694,604	113,494,491	119,362,029	122,695,718
Common Stock Outstanding, beginning balance	1,067,211,953	1,064,412,066	1,022,025,965	974,378,820
Common Stock Outstanding, ending balance	1,067,211,953	1,064,412,066	1,022,025,965	974,378,820