Debt (Tables)

6 Months Ended

Jun. 30, 2012

Debt [Abstract]

Total debt, including the current portion of long-term debt

(millions)	As of June 30, 2012		As of December 31, 2011
9.75% senior notes due 2014, net of discount	$	59	$	297
8.375% senior notes due 2018		350		350
7.875% senior notes due 2020, net of discount		248		—
7.75% senior notes due 2018, net of discount		499		499
6.3% senior notes due 2016		500		500
10% convertible senior notes due 2018, net of discount		384		383
Ship mortgage facility (includes $7 million of current portion of long-term debt)		33		36
Industrial revenue bonds (due 2028 through 2034)		239		239
Total	$	2,312	$	2,304