Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement Of Partners Capital [Abstract]
Net income	$ 1,918,080	$ 1,408,306	$ 1,315,114
Other comprehensive income (loss), net of tax and reclassification adjustments:
Net unrealized losses on investment securities	(86,523)	(19,766)	(64,406)
Cash flow hedges adjustments	6,091	(9,912)	(94)
Foreign currency translation adjustment	(2,225)	2,241	(2,614)
Defined benefit plans liability adjustments	43,243	22,288	24,105
Total other comprehensive loss	(39,414)	(5,149)	(43,009)
Total comprehensive income	$ 1,878,666	$ 1,403,157	$ 1,272,105