Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Partners Capital [Abstract]
Net income	$ 1,315,114	$ 1,079,667	$ 1,066,246
Other comprehensive income (loss), net of tax and reclassification adjustments:
Net unrealized gains (losses) on investment securities	(64,406)	(79,114)	93,275
Cash flow hedges adjustments	(94)	796	(96)
Foreign currency translation adjustment	(2,614)	(925)	(2,607)
Defined benefit plans liability adjustments	24,105	8,610	(207,407)
Total other comprehensive loss	(43,009)	(70,633)	(116,835)
Total comprehensive income	$ 1,272,105	$ 1,009,034	$ 949,411