EXHIBIT 12

COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES

The ratio of earnings to fixed charges is calculated using the Securities and Exchange Commission guidelines.

	Year Ended December 31,
	2007		2006		2005		2004		2003
	(dollars in millions)
Earnings as defined for fixed charges calculation
Add:
Pretax income	$	386	$	200	$	325	$	277	$	234
Fixed charges		130		145		126		103		97
Deduct:
Interest capitalized(a)		11		16		8		2		5
Total earnings (as defined for the Fixed Charges calculation)	$	505	$	329	$	443	$	378	$	326
Fixed charges:
Interest on debt, including capitalized portions	$	120	$	138	$	118	$	93	$	88
Estimate of interest within rental expense		10		7		8		10		9
Total fixed charges	$	130	$	145	$	126	$	103	$	97
Ratio of earnings to fixed charges		3.9		2.3		3.5		3.7		3.4

(a) Excludes equity costs related to AFUDC that are included in Other Income and Expenses in the Consolidated Statements of Operations.