Derivatives (Notional and Fair Values) (Details) MMBTU in Thousands, Boe in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2021 USD ($) MMBTU Boe company	Dec. 31, 2020 USD ($) MMBTU Boe company
Derivative Asset [Abstract]
Derivative assets - Fair value	$ 588,582	$ 602,754
Less: Master netting agreements	(89,723)	(93,063)
Less: Cash collateral received/paid	(3,368)	(8,449)
Net derivative assets	495,491	501,242
Derivative Liability [Abstract]
Derivative liabilities - Fair value	448,921	424,828
Less: Master netting agreements	(89,723)	(93,063)
Less: Cash collateral received/paid	(163,586)	(91,634)
Net derivative liabilities	$ 195,612	$ 240,131
Crude oil \| Customer Counterparty
Derivative Liability [Abstract]
Derivative, nonmonetary notional amount, energy measure \| Boe	8,484	6,321
Natural gas \| Customer Counterparty
Derivative Liability [Abstract]
Derivative, nonmonetary notional amount, energy measure \| MMBTU	119,921	109,635
Derivative instruments designated as hedging instruments
Derivative Instruments
Notional Amount	$ 360,176	$ 359,269
Derivative Asset [Abstract]
Derivative assets - Fair value	0	0
Derivative Liability [Abstract]
Derivative liabilities - Fair value	1,379	2,099
Derivative instruments designated as hedging instruments \| Cash Flow Hedging \| Interest rate contracts
Derivative Instruments
Notional Amount	275,000	275,000
Derivative Asset [Abstract]
Derivative assets - Fair value	0	0
Derivative Liability [Abstract]
Derivative liabilities - Fair value	1,184	1,864
Derivative instruments designated as hedging instruments \| Net Investment Hedging \| Foreign exchange contracts
Derivative Instruments
Notional Amount	85,176	84,269
Derivative Asset [Abstract]
Derivative assets - Fair value	0	0
Derivative Liability [Abstract]
Derivative liabilities - Fair value	195	235
Derivatives not designated as hedging instruments
Derivative Instruments
Notional Amount	21,676,672	21,341,158
Derivative Asset [Abstract]
Derivative assets - Fair value	588,582	602,754
Derivative Liability [Abstract]
Derivative liabilities - Fair value	447,542	422,729
Derivatives not designated as hedging instruments \| Interest rate contracts
Derivative Instruments
Notional Amount	17,836,695	18,155,678
Derivative Asset [Abstract]
Derivative assets - Fair value	329,953	489,132
Derivative Liability [Abstract]
Derivative liabilities - Fair value	227,768	315,834
Derivatives not designated as hedging instruments \| Foreign exchange contracts
Derivative Instruments
Notional Amount	3,756,284	3,108,488
Derivative Asset [Abstract]
Derivative assets - Fair value	29,867	30,300
Derivative Liability [Abstract]
Derivative liabilities - Fair value	20,360	22,524
Derivatives not designated as hedging instruments \| Credit contracts
Derivative Instruments
Notional Amount	83,693	76,992
Derivative Asset [Abstract]
Derivative assets - Fair value	3	13
Derivative Liability [Abstract]
Derivative liabilities - Fair value	87	206
Derivatives not designated as hedging instruments \| Equity contracts
Derivative Instruments
Notional Amount	0	0
Derivative Asset [Abstract]
Derivative assets - Fair value	223	858
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	228,536	82,451
Derivative Liability [Abstract]
Derivative liabilities - Fair value	$ 199,327	$ 84,165
Derivatives not designated as hedging instruments \| Equity, Public Companies
Derivative Liability [Abstract]
Number of companies that issued the equity (issuers portion only) \| company		2
Derivatives not designated as hedging instruments \| Equity, Private Companies
Derivative Liability [Abstract]
Number of companies that issued the equity (issuers portion only) \| company	14	17

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