Aon (AON) 10-Q 2011 Q3 Quarterly report

Exhibit 12.1

Aon Corporation and Consolidated Subsidiaries

Combined With Unconsolidated Subsidiaries

Computation of Ratio of Earnings to Fixed Charges

	Nine Months ended
	September 30,					Years Ended December 31,
(millions except ratio)	2011			2010		2010			2009		2008		2007		2006
Income from continuing operations before income taxes and noncontrolling interests	$	1,000		$	699	$	1,059		$	949	$	879	$	1,023	$	738
Less: Equity in earnings on less than 50% owned entities	(7		)	3		10			11		5		6		5
Add back fixed charges:
Interest on indebtedness	186			117		182			122		126		138		129
Interest on uncertain tax positions	1			1		(1		)	2		—		2		—
Portion of rents representative of interest factor	37			29		48			48		47		75		79
Income as adjusted	$	1,231		$	843	$	1,278		$	1,110	$	1,047	$	1,232	$	941
Fixed charges:
Interest on indebtedness	$	186		$	117	$	182		$	122	$	126	$	138	$	129
Interest on uncertain tax positions	1			1		(1		)	2		—		2		—
Portion of rents representative of interest factor	37			29		48			48		47		75		79
Total fixed charges	$	224		$	147	$	229		$	172	$	173	$	215	$	208
Ratio of earnings to fixed charges	5.5			5.7		5.6			6.5		6.1		5.7		4.5