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Income Taxes - Difference Between Effective Tax Rate (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Income Tax Disclosure [Abstract] |  |  |
Federal income tax at U.S. statutory rate | $ (1,357) | $ 9 | $ (137)
Foreign income tax rate differential | (40) | (3) | (21)
Goodwill impairment | 666 |  |
Nondeductible expenses | 61 | 20 | 38
Foreign dividends, net of foreign tax credits | 163 | 27 | (132)
Tax rate change on timing differences | 1 | (7) | (245)
Change in uncertain tax positions | (60) | (5) | 81
Prior years taxes | 3 | (13) | (26)
Tax impact on foreign exchange | (2) | (3) | 5
Change in deferred tax valuation allowance | 218 | 49 | 280
State income taxes - net of federal benefit | (16) | (3) | (1)
Tax exempt income | (6) | (5) |
Income tax credits |  | (3) | (4)
Other |  |  | 6
Total income tax provision | $ (369) | $ 63 | $ (156)

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