Consolidated Statement of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Statement of Partners' Capital [Abstract]
Net income	$ 241,613us-gaap_NetIncomeLoss	$ 229,017us-gaap_NetIncomeLoss
Other comprehensive income, net of tax and reclassification adjustments:
Net unrealized gains on investment securities	25,339	38,214
Cash flow hedges adjustments	871
Foreign currency translation adjustment	(2,384)	(136)
Defined benefit plans liability adjustment	4,677	820
Total other comprehensive income	28,503	38,898
Total comprehensive income	$ 270,116us-gaap_ComprehensiveIncomeNetOfTax	$ 267,915us-gaap_ComprehensiveIncomeNetOfTax

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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Amount after tax and reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.

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