Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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- Definition

Amount of the cumulative effect on retained earnings net of related income tax effect.

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- Definition

Amount after tax and reclassification adjustments of other comprehensive income (loss).

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- Definition

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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Comprehensive Income - Accumulated Other Comprehensive Income (Loss), Net (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			$ 16,250,819	$ 16,486,622
Cumulative effect of change in accounting principle — equity securities			(16,853)
Net gain (loss) during period	$ (24,458)	$ 22,166	(161,732)	46,721
Ending balance	15,436,085	16,318,052	15,436,085	16,318,052
Investment Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(44,150)
Cumulative effect of change in accounting principle — equity securities			(16,853)
Net gain (loss) during period			(167,798)
Ending balance	(228,801)		(228,801)
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(304,546)
Net gain (loss) during period			21,447
Ending balance	(283,099)		(283,099)
Accumulated Other Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(15,118)
Net gain (loss) during period			(15,381)
Ending balance	(30,499)		(30,499)
Accumulated Other Comprehensive Income (Loss), Net [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(363,814)	(294,636)
Cumulative effect of change in accounting principle — equity securities			(16,853)
Net gain (loss) during period			(161,732)
Ending balance	$ (542,399)	$ (247,915)	$ (542,399)	$ (247,915)