Income Taxes - Components of Aon's deferred tax assets and liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Employee benefit plans	$ 635	$ 739
Net operating/capital loss and tax credit carryforwards	349	295
Accrued interest	293	303
Other accrued expenses	98	44
Deferred revenue	65	40
Investment basis differences	56	45
Other	56	6
Total	1,552	1,472
Valuation allowance on deferred tax assets	(175)	(205)
Total	1,377	1,267
Deferred tax liabilities:
Intangibles and property, plant and equipment	(961)	(1,058)
Other accrued expenses	(99)	(40)
Deferred costs	(30)	(28)
Unrealized foreign exchange gains	(29)	(44)
Unremitted earnings	(18)	(28)
Other	(44)	(28)
Total	(1,181)	(1,226)
Net deferred tax asset	$ 196	$ 41

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.