Share-Based Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2012

Share-Based Compensation Plans

Share-based compensation expense recognized in continuing operations

 The following table summarizes share-based compensation expense recognized in the Consolidated Statements of Income in Compensation and benefits (in millions):

Years ended December 31	2012		2011		2010
Restricted share units ("RSUs")	$	154	$	142	$	138
Performance share awards ("PSAs")		46		78		62
Share options		5		9		17
Employee share purchase plans		7		6		4
Total share-based compensation expense		212		235		221
Tax benefit		62		77		75
Share-based compensation expense, net of tax	$	150	$	158	$	146

Restricted share unit activity

 A summary of the status of Aon's RSUs is as follows (shares in thousands):

	2012					2011					2010
Years ended December 31	Shares			Fair Value (1)		Shares			Fair Value (1)		Shares			Fair Value (1)
Non-vested at beginning of year		9,916		$	42		10,674		$	38		12,850		$	36
Granted		5,113			46		3,506			51		3,817			40
Vested		(3,958	)		42		(3,773	)		39		(5,278	)		35
Forfeited		(639	)		44		(491	)		39		(715	)		35
Non-vested at end of year		10,432			44		9,916			42		10,674			38

(1)

Represents per share weighted average fair value of award at date of grant.

Performance-based plans

 Information regarding PSAs granted during the years ended December 31, 2012, 2011 and 2010 follows (shares in thousands, dollars in millions, except fair value):

	2012		2011		2010
Target PSAs granted		1,369		1,715		1,390
Fair Value (1)	$	47	$	50	$	39
Number of shares that would be issued based on current performance levels		1,722		1,120		1,079
Unamortized expense, based on current performance levels	$	63	$	19	$	—

(1)

Represents per share weighted average fair value of award at date of grant.

Weighted average assumptions, average expected life and estimated fair value of employee stock options

Years ended December 31	2012	2011			2010
	All Other Options	All Other Options			All Other Options
Weighted average volatility	NA		26.1	%		28.5	%
Expected dividend yield	NA		1.3	%		1.6	%
Risk-free rate	NA		2.2	%		3.0	%
Weighted average expected life, in years	NA		5.5			6.1
Weighted average estimated fair value per share	NA	$	10.92		$	10.37

Share options and related information

 A summary of the status of the Company's share options and related information is as follows (shares in thousands):

Years ended December 31	2012					2011					2010
	Shares			Weighted- Average Exercise Price Per Share		Shares			Weighted- Average Exercise Price Per Share		Shares			Weighted- Average Exercise Price Per Share
Beginning outstanding		9,116		$	32		13,919		$	32		15,937		$	33
Options issued in connection with the Hewitt acquisition		—			—		—			—		4,545			22
Granted		—			—		80			53		143			38
Exercised		(3,413	)		31		(4,546	)		32		(6,197	)		27
Forfeited and expired		(92	)		37		(337	)		36		(509	)		35
Outstanding at end of year		5,611			32		9,116			32		13,919			32
Exercisable at end of year		5,117			31		7,833			30		11,293			30
Shares available for grant		17,024					24,508					22,777

Summary of options outstanding and exercisable

A summary of options outstanding and exercisable as of December 31, 2012 is as follows (shares in thousands):

	Options Outstanding						Options Exercisable
Range of Exercise Prices	Shares Outstanding		Weighted- Average Remaining Contractual Life (years)		Weighted- Average Exercise Price Per Share		Shares Exercisable		Weighted- Average Remaining Contractual Life (years)		Weighted- Average Exercise Price Per Share
$14.71 – 22.86		1,747		2.07	$	21.72		1,747		2.07	$	21.72
22.87 – 25.51		331		2.43		25.40		331		2.43		25.40
25.52 – 32.53		675		1.74		27.30		675		1.74		27.30
32.54 – 36.88		631		2.99		35.89		482		2.57		35.73
36.89 – 43.44		1,393		2.81		39.50		1,238		2.37		39.58
43.45 – 52.93		834		3.79		46.54		644		3.32		45.64
		5,611						5,117

Other information related to the company's share options

 Other information related to the Company's share options is as follows (in millions):

	2012		2011		2010
Aggregate intrinsic value of stock options exercised	$	67	$	80	$	87
Cash received from the exercise of stock options		105		153		162
Tax benefit realized from the exercise of stock options		11		14		4