Derivatives (Narrative) (Details) MMBTU in Thousands, Boe in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2020 USD ($) Boe MMBTU company	Dec. 31, 2019 USD ($) MMBTU Boe company
Derivative [Line Items]
Derivative liabilities - Fair Value	$ 424,828	$ 256,528
Derivative assets - Fair value	$ 602,754	330,316
Foreign exchange contracts
Derivative [Line Items]
Original maturity (in years)	1 year
Credit-Risk-Related Contingent Features
Derivative [Line Items]
Associated posted collateral	$ 106,800	56,400
Aggregate fair value of derivative instruments in net liability position	107,400	56,400
Derivative instruments designated as hedging instruments
Derivative [Line Items]
Notional amount	359,269	117,193
Derivative liabilities - Fair Value	2,099	4,784
Derivative assets - Fair value	0	0
Derivative instruments designated as hedging instruments \| Foreign exchange contracts \| Derivative Financial Instruments, Liabilities
Derivative [Line Items]
Notional amount	84,300	86,200
Derivative liabilities - Fair Value	235	1,600
Derivative instruments designated as hedging instruments \| Interest rate contracts \| Cash Flow Hedging
Derivative [Line Items]
Notional amount	275,000	0
Net unrealized gains, net of tax, recorded in AOCI expected to be reclassified into earnings during the next 12 months	599
Derivative liabilities - Fair Value	1,864	0
Derivative assets - Fair value	0	0
Derivative instruments not designated as hedging instruments
Derivative [Line Items]
Notional amount	21,341,158	20,540,031
Derivative liabilities - Fair Value	422,729	251,744
Derivative assets - Fair value	602,754	330,316
Derivative instruments not designated as hedging instruments \| Foreign exchange contracts
Derivative [Line Items]
Notional amount	3,108,488	4,839,661
Derivative liabilities - Fair Value	22,524	47,024
Derivative assets - Fair value	30,300	54,637
Derivative instruments not designated as hedging instruments \| Interest rate contracts
Derivative [Line Items]
Notional amount	18,155,678	15,489,692
Derivative liabilities - Fair Value	315,834	124,119
Derivative assets - Fair value	489,132	192,883
Derivative instruments not designated as hedging instruments \| Credit contracts
Derivative [Line Items]
Notional amount	76,992	210,678
Derivative liabilities - Fair Value	206	84
Derivative assets - Fair value	$ 13	$ 2
Weighted average remaining maturity of outstanding RPAs	3 years 8 months 12 days	2 years 2 months 12 days
Derivative instruments not designated as hedging instruments \| Credit contracts \| RPAs - protection sold
Derivative [Line Items]
Maximum exposure of RPAs with protection sold	$ 662	$ 125
Derivative instruments not designated as hedging instruments \| Equity, Private Companies
Derivative [Line Items]
Number of companies that Issued the equity contracts (Issuers Portion Only) \| company	17	18
Derivative instruments not designated as hedging instruments \| Equity, Public Companies
Derivative [Line Items]
Number of companies that Issued the equity contracts (Issuers Portion Only) \| company	2	3
Derivative instruments not designated as hedging instruments \| Equity contracts
Derivative [Line Items]
Notional amount	$ 0	$ 0
Derivative liabilities - Fair Value	0	0
Derivative assets - Fair value	858	1,414
Derivative instruments not designated as hedging instruments \| Commodity contracts
Derivative [Line Items]
Notional amount	0	0
Derivative liabilities - Fair Value	84,165	80,517
Derivative assets - Fair value	82,451	81,380
Fair Value, Measurements, Recurring
Derivative [Line Items]
Derivative liabilities - Fair Value	424,828	256,528
Derivative assets - Fair value	602,754	330,316
Fair Value, Measurements, Recurring \| Foreign exchange contracts
Derivative [Line Items]
Derivative liabilities - Fair Value	22,759	48,610
Derivative assets - Fair value	30,300	54,637
Fair Value, Measurements, Recurring \| Interest rate contracts
Derivative [Line Items]
Derivative liabilities - Fair Value	317,698	127,317
Derivative assets - Fair value	489,132	192,883
Fair Value, Measurements, Recurring \| Credit contracts
Derivative [Line Items]
Derivative liabilities - Fair Value	206	84
Derivative assets - Fair value	13	2
Fair Value, Measurements, Recurring \| Equity contracts
Derivative [Line Items]
Derivative assets - Fair value	858	1,414
Fair Value, Measurements, Recurring \| Commodity contracts
Derivative [Line Items]
Derivative liabilities - Fair Value	84,165	80,517
Derivative assets - Fair value	82,451	81,380
Financial Counterparty \| Derivative instruments not designated as hedging instruments \| Interest rate contracts
Derivative [Line Items]
Notional amount	9,090,000	7,750,000
London Clearing House \| Derivative instruments not designated as hedging instruments \| Interest rate contracts
Derivative [Line Items]
Notional amount	2,980,000	2,530,000
Derivative liabilities - Fair Value	187,400	75,100
Derivative assets - Fair value	1,300	2,900
Chicago Mercantile Exchange (CME) \| Derivative instruments not designated as hedging instruments \| Commodity contracts
Derivative [Line Items]
Derivative liabilities - Fair Value	3,700	1,500
Derivative assets - Fair value	7,900	2,900
Derivative assets (liabilities), at fair value, net	$ 0	$ 986
Chicago Mercantile Exchange (CME) \| Derivative instruments not designated as hedging instruments \| Commodity contracts \| Oil
Derivative [Line Items]
Derivative, nonmonetary notional amount, energy measure \| Boe	1,275	1,752
Chicago Mercantile Exchange (CME) \| Derivative instruments not designated as hedging instruments \| Commodity contracts \| Natural Gas
Derivative [Line Items]
Derivative, nonmonetary notional amount, energy measure \| MMBTU	29,733	6,075

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Number of Companies that Issued the Warrants (Issuers Portion Only)

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The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features.

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Maximum potential amount of future undiscounted payments that could be required under the credit derivative, before reduction for potential recoveries under recourse or collateralization provisions.

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Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

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Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and elected not to be offset.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain (loss) on that instrument.

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Nominal energy measure used to calculate payments on a derivative instrument.

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