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Income Taxes - Difference Between Effective Tax Rate (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Federal income tax at U.S. statutory rate	$ 9	$ (137)	$ (918)
Foreign income tax rate differential	(3)	(21)	32
Goodwill impairment			271
Nondeductible expenses	20	38	30
Foreign dividends, net of foreign tax credits	27	(132)	(25)
Tax rate change on timing differences	(7)	(245)	(8)
Change in uncertain tax positions	(5)	81	11
Prior years taxes	(13)	(26)	(29)
Tax impact on foreign exchange	(3)	5	(4)
Change in deferred tax valuation allowance	49	280	476
State income taxes - net of federal benefit	(3)	(1)	(10)
Tax exempt income	(5)		(7)
Income tax credits	(3)	(4)
Other		6	(26)
Total income tax provision	$ 63	$ (156)	$ (207)

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