Derivative Financial Instruments (Location and Amount of Fair Value And Cash Flow Hedge Derivative Gains And Losses Recorded In Income) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Derivative Instruments, Gain (Loss) [Line Items]
Interest Income	$ 2,530.2	$ 1,935.0	$ 7,482.3	$ 5,125.4
Interest Expense	1,967.9	1,478.8	5,869.0	3,626.5
Other Operating Income	111.8	68.2	1,097.5	170.2
INTEREST INCOME
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) recognized on fair value hedges	29.3	11.1	79.9	34.7
Gains (Losses) on cash flow hedges recognized on	0.6	14.6	7.1	15.8
INTEREST EXPENSE
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) recognized on fair value hedges	(20.1)	(24.9)	(59.9)	(65.9)
Gains (Losses) on cash flow hedges recognized on	0.0	0.0	0.0	0.0
OTHER OPERATING INCOME
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) recognized on fair value hedges	0.0	0.0	0.0	0.0
Gains (Losses) on cash flow hedges recognized on	0.0	0.3	0.0	1.9
Interest Rate Contracts \| INTEREST INCOME
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	(251.6)	14.1	(94.1)	0.6
Recognized on hedged items	251.6	(14.1)	94.1	(0.6)
Amounts related to interest settlements on derivatives	29.3	11.1	79.9	34.7
Interest Rate Contracts \| INTEREST EXPENSE
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	76.5	(41.8)	46.5	(42.5)
Recognized on hedged items	(76.5)	41.8	(46.5)	42.5
Amounts related to interest settlements on derivatives	(20.1)	(24.9)	(59.9)	(65.9)
Interest Rate Contracts \| OTHER OPERATING INCOME
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	0.0	0.0	0.0	0.0
Recognized on hedged items	0.0	0.0	0.0	0.0
Amounts related to interest settlements on derivatives	0.0	0.0	0.0	0.0
Foreign Exchange Contracts \| INTEREST INCOME
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) on cash flow hedges recognized on	0.6	14.6	7.1	15.8
Foreign Exchange Contracts \| INTEREST EXPENSE
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) on cash flow hedges recognized on	0.0	0.0	0.0	0.0
Foreign Exchange Contracts \| OTHER OPERATING INCOME
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) on cash flow hedges recognized on	$ 0.0	$ 0.3	$ 0.0	$ 1.9

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Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

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