Consolidated Statement of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Statement Of Partners Capital [Abstract]
Net income	$ 348,466	$ 233,380	$ 622,579	$ 439,843
Other comprehensive income, net of tax and reclassification adjustments:
Net unrealized gains (losses) on investment securities	(6,722)	49,289	3,357	69,371
Reclassification to income for amortization of gains on terminated cash flow hedges		(42)		(112)
Foreign currency translation adjustment	(114)	(533)	(1,046)	(131)
Defined benefit plans liability adjustment	5,018	4,695	10,182	9,464
Total other comprehensive income	(1,818)	53,409	12,493	78,592
Total comprehensive income	$ 346,648	$ 286,789	$ 635,072	$ 518,435