Income Taxes - Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Net operating loss, capital loss and credits	$ 86	$ 78
Accruals and allowances	129	222
Stock-based compensation	40	65
Amortizable tax basis in intangibles	5,164	4,621
Net deferred tax assets	5,419	4,986
Valuation allowance	(19)	(37)
Deferred tax assets, net of valuation allowance	5,400	4,949
Deferred tax liabilities:
Unremitted foreign earnings	(3,514)	(1,578)
Acquisition-related intangibles	(24)	(29)
Depreciation and amortization	(89)	(158)
Available-for-sale securities	(4)	(29)
Deferred tax liabilities	(3,631)	(1,794)
Net deferred tax assets	$ 1,769	$ 3,155

The sum of the tax effects as of the balance sheet date of the amount of excesses 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.

No definition available.