Income taxes (Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred income tax assets:
NOL and credit carryforwards	$ 800	$ 810
Accrued expenses	457	428
Expenses capitalized for tax	170	185
Stock-based compensation	91	95
Other	269	174
Total deferred income tax assets	1,787	1,692
Valuation allowance	(517)	(509)
Net deferred income tax assets	1,270	1,183
Deferred income tax liabilities:
Acquired intangible assets	(1,288)	(1,509)
Debt	(210)	(184)
Other	(286)	(267)
Total deferred income tax liabilities	(1,784)	(1,960)
Total deferred income taxes, net	$ (514)	$ (777)

The tax effect as of the balance sheet date of the amount of the estimated future tax deductions arising from acquired net operating loss and credit carryforwards and which can only be realized if sufficient tax-basis income is generated in future periods to enable the deduction to be taken.

No definition available.