Consolidated Statement of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement Of Partners Capital [Abstract]
Net income	$ 294,479	$ 293,462	$ 917,058	$ 733,305
Other comprehensive income, net of tax and reclassification adjustments:
Net unrealized gains on investment securities	23,367	42,560	26,724	111,931
Reclassification to income for amortization of gains on terminated cash flow hedges				(112)
Foreign currency translation adjustment	1,251	482	205	351
Defined benefit plans liability adjustment	5,091	4,732	15,273	14,196
Total other comprehensive income	29,709	47,774	42,202	126,366
Total comprehensive income	$ 324,188	$ 341,236	$ 959,260	$ 859,671