Consolidated Statement of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement Of Partners Capital [Abstract]
Net income	$ 493,160	$ 381,053	$ 845,770	$ 729,980
Other comprehensive income, net of tax and reclassification adjustments:
Net unrealized gains (losses) on investment securities	(36,733)	16,932	(137,417)	15,576
Cash flow hedges adjustments	(2,569)	(955)	(13,011)	(978)
Foreign currency translation adjustment	(2,434)	1,150	(1,144)	1,626
Defined benefit plans liability adjustments	7,038	4,359	14,298	8,331
Total other comprehensive income (loss)	(34,698)	21,486	(137,274)	24,555
Total comprehensive income	$ 458,462	$ 402,539	$ 708,496	$ 754,535

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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