Exhibit 12.1

COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES

	March 31,		Year ended December 31,
	2009		2008			2007			2006		2005		2004
	(millions except ratios)
Income before income taxes, equity in net income of associates and noncontrolling interest	$	236	$	399		$	554		$	514	$	421	$	591
Add back fixed charges:
Total fixed charges	46		150			106			66		53		48
Dividends from associates	—		9			6			5		5		7
Less:
Capitalized interest	—		(1		)	(2		)	—		—		—
Income as adjusted	$	282	$	557		$	664		$	585	$	479	$	646
Fixed charges
Interest expense	$	38	$	105		$	66		$	38	$	30	$	22
Portions of rents representative of interest factor	8		45			40			28		23		26
Total fixed charges	$	46	$	150		$	106		$	66	$	53	$	48
Ratio of earnings to fixed charges	6.1		3.7			6.3			8.9		9.0		13.5

COMPUTATION OF RATIO OF EARNINGS TO COMBINED FIXED CHARGES AND PREFERRED STOCK DIVIDENDS

	March 31,		Year ended December 31,
	2009		2008			2007			2006		2005		2004
	(millions except ratios)
Income before income taxes, equity in net income of associates and noncontrolling interest	$	236	$	399		$	554		$	514	$	421	$	591
Add back fixed charges:
Total fixed charges	46		150			106			66		53		48
Dividends from associates	—		9			6			5		5		7
Less:
Capitalized interest	—		(1		)	(2		)	—		—		—
Income as adjusted	$	282	$	557		$	664		$	585	$	479	$	646
Fixed charges and preferred stock dividends
Interest expense	$	38	$	105		$	66		$	38	$	30	$	22
Portions of rents representative of interest factor	8		45			40			28		23		26
Total fixed charges	$	46	$	150		$	106		$	66	$	53	$	48
Preferred stock dividends	—		—			—			—		—		—
Total fixed charges and preferred stock dividends	$	46	$	150		$	106		$	66	$	53	$	48
Ratio of earnings to combined fixed charges and preferred stock dividends	6.1		3.7			6.3			8.9		9.0		13.5