Income Taxes Components of Aon's deferred tax assets and liabilities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets:
Employee benefit plans	$ 623	$ 917
Net operating/capital loss and tax credit carryforwards	354	368
Other accrued expenses	142	47
Investment basis differences	50	13
Other	58	77
Total	1,227	1,422
Valuation allowance on deferred tax assets	(127)	(154)
Total	1,100	1,268
Deferred tax liabilities:
Intangibles and property, plant and equipment	(1,074)	(1,128)
Unremitted earnings	(51)	0
Deferred revenue	(27)	(30)
Other accrued expenses	(39)	(62)
Unrealized investment gains	0	(5)
Unrealized foreign exchange gains	(27)	(8)
Other	(64)	(29)
Total	(1,282)	(1,262)
Net deferred tax asset (liability)	$ (182)	$ 6

The sum of the tax effects as of the balance sheet date of the amount of (1) excess of tax deductions over gross income in a year which cannot be used on the tax returns in the current year but can be carried forward to reduce taxable income or income taxes payable in a future year, for which there must be sufficient tax-basis income to utilize a portion or all of the carryforward amount to realize the deferred tax asset, and capital losses that cannot be utilized on the tax return during a period that have been carried forward to reduce taxable income or taxes payable in a future year and (2) future tax deductions arising from all unused tax credit carryforwards which have been reduced by a valuation allowance.

No definition available.