Derivatives (Notional and Fair Values) (Details) MMBTU in Thousands, Boe in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2020 USD ($) Boe MMBTU company	Dec. 31, 2019 USD ($) Boe MMBTU company
Derivative Asset [Abstract]
Derivative assets - Fair value	$ 764,430	$ 330,316
Less: Master netting agreements	(110,569)	(121,561)
Less: Cash collateral received/paid	(11,649)	(3,758)
Derivative asset, after netting	642,212	204,997
Derivative Liability [Abstract]
Derivative liabilities - Fair value	560,169	256,528
Less: Master netting agreements	(110,569)	(121,561)
Less: Cash collateral received/paid	(94,435)	(38,238)
Derivative liability, after netting	$ 355,165	$ 96,729
Crude oil \| Customer Counterparty
Derivative Liability [Abstract]
Derivative, nonmonetary notional amount, energy measure \| Boe	6,155	7,811
Natural gas \| Customer Counterparty
Derivative Liability [Abstract]
Derivative, nonmonetary notional amount, energy measure \| MMBTU	84,957	63,773
Derivative instruments designated as hedging instruments
Derivative Instruments
Notional amount	$ 367,883	$ 117,193
Derivative Asset [Abstract]
Derivative assets - Fair value	245	0
Derivative Liability [Abstract]
Derivative liabilities - Fair value	1,657	4,784
Derivative instruments designated as hedging instruments \| Fair Value Hedging \| Interest rate contracts
Derivative Instruments
Notional amount	15,194	31,026
Derivative Asset [Abstract]
Derivative assets - Fair value	0	0
Derivative Liability [Abstract]
Derivative liabilities - Fair value	174	3,198
Derivative instruments designated as hedging instruments \| Cash Flow Hedging \| Interest rate contracts
Derivative Instruments
Notional amount	275,000	0
Derivative Asset [Abstract]
Derivative assets - Fair value	0	0
Derivative Liability [Abstract]
Derivative liabilities - Fair value	1,483	0
Derivative instruments designated as hedging instruments \| Net Investment Hedging \| Foreign exchange contracts
Derivative Instruments
Notional amount	77,689	86,167
Derivative Asset [Abstract]
Derivative assets - Fair value	245	0
Derivative Liability [Abstract]
Derivative liabilities - Fair value	0	1,586
Derivatives not designated as hedging instruments
Derivative Instruments
Notional amount	20,113,400	20,540,031
Derivative Asset [Abstract]
Derivative assets - Fair value	764,185	330,316
Derivative Liability [Abstract]
Derivative liabilities - Fair value	558,512	251,744
Derivatives not designated as hedging instruments \| Interest rate contracts
Derivative Instruments
Notional amount	17,170,884	15,489,692
Derivative Asset [Abstract]
Derivative assets - Fair value	613,480	192,883
Derivative Liability [Abstract]
Derivative liabilities - Fair value	400,146	124,119
Derivatives not designated as hedging instruments \| Foreign exchange contracts
Derivative Instruments
Notional amount	2,738,018	4,839,661
Derivative Asset [Abstract]
Derivative assets - Fair value	24,044	54,637
Derivative Liability [Abstract]
Derivative liabilities - Fair value	19,741	47,024
Derivatives not designated as hedging instruments \| Credit contracts
Derivative Instruments
Notional amount	204,498	210,678
Derivative Asset [Abstract]
Derivative assets - Fair value	41	2
Derivative Liability [Abstract]
Derivative liabilities - Fair value	327	84
Derivatives not designated as hedging instruments \| Equity contracts
Derivative Instruments
Notional amount	0	0
Derivative Asset [Abstract]
Derivative assets - Fair value	9,173	1,414
Derivative Liability [Abstract]
Derivative liabilities - Fair value	0	0
Derivatives not designated as hedging instruments \| Commodity contracts
Derivative Instruments
Notional amount	0	0
Derivative Asset [Abstract]
Derivative assets - Fair value	117,447	81,380
Derivative Liability [Abstract]
Derivative liabilities - Fair value	$ 138,298	$ 80,517
Derivatives not designated as hedging instruments \| Equity, Public Companies
Derivative Liability [Abstract]
Number of companies that issued the equity (issuers portion only) \| company	3	3
Derivatives not designated as hedging instruments \| Equity, Private Companies
Derivative Liability [Abstract]
Number of companies that issued the equity (issuers portion only) \| company	17	18

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