Income Taxes - Components of Income Tax Expense (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Federal
Current	$ 455	$ 717	$ 1,479	$ 1,631
Deferred	54	(232)	(103)	(279)
Federal income tax	509	485	1,376	1,352
State
Current	53	108	199	235
Deferred	27	(27)	64	25
State income tax	80	81	263	260
Applicable income taxes	$ 589	$ 566	$ 1,639	$ 1,612

Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.

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