Restructuring (Tables)

12 Months Ended

Dec. 31, 2013

Restructuring Cost and Reserve [Line Items]

Schedule of changes in company's liabilities for its restructuring plans

As of December 31, 2013, the Company's liabilities for its restructuring plans are as follows (in millions):

	Aon Hewitt Plan			Aon Benfield Plan			2007 Plan			Other			Total
Balance at January 1, 2011	$	88		$	26		$	113		$	10		$	237
Expensed	98			19			(11		)	—			106
Cash payments	(93		)	(24		)	(59		)	(2		)	(178		)
Foreign exchange translation and other	2			(1		)	7			—			8
Balance at December 31, 2011	$	95		$	20		$	50		$	8		$	173
Expensed	94			6			(3		)	—			97
Cash payments	(95		)	(24		)	(18		)	(5		)	(142		)
Stock compensation	—			(1		)	—			—			(1		)
Foreign exchange translation and other	2			2			6			—			10
Balance at December 31, 2012	$	96		$	3		$	35		$	3		$	137
Expensed	167			—			—			—			167
Cash payments	(125		)	(2		)	(24		)	(1		)	(152		)
Foreign exchange and other	5			—			9			—			14
Balance at December 31, 2013	$	143		$	1		$	20		$	2		$	166

Aon Hewitt Restructuring Plan [Member]

Restructuring Cost and Reserve [Line Items]

Schedule of restructuring and related expenses by type

The following summarizes restructuring and related costs by type that were incurred through the end of the restructuring initiative related to the Aon Hewitt Plan (in millions):

	2010		2011		2012		2013		Completed Plan Total
Workforce reduction	$	49	$	64	$	74	$	79	$	266
Lease consolidation	3		32		18		83		136
Asset impairments	—		7		4		7		18
Other costs associated with restructuring (1)	—		2		2		5		9
Total restructuring and related expenses	$	52	$	105	$	98	$	174	$	429

(1) Other costs associated with restructuring initiatives, including moving costs and consulting and legal fees, are recognized when incurred.

Aon Hewitt Restructuring Plan [Member] | Total operating segments [Member]

Restructuring Cost and Reserve [Line Items]

Schedule of restructuring and related expenses by type

The following summarizes the restructuring and related expenses, by segment, that have been incurred through the end of the restructuring initiative related to the Aon Hewitt Plan (in millions):

	2010		2011		2012		2013		Completed Plan Total
HR Solutions	$	52	$	49	$	66	$	80	$	247
Risk Solutions	—		56		32		94		182
Total restructuring and related expenses	$	52	$	105	$	98	$	174	$	429

(1) Costs included in the Risk Solutions segment are due to the inclusion of the health and benefits consulting business in the Risk Solutions segment, which was transfered from HR Solutions effective January 1, 2012. Costs incurred in 2011 in the HR Solutions segment of $41 million related to the health and benefits consulting business have been reclassified and presented in the Risk Solutions segment.