Derivatives and Hedging Activities - Effect of Fair Value and Cash Flow Hedges on Income (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense — Long-term debt		$ (61)	$ (54)	$ (110)	$ (114)
Interest income — Loans		923	888	1,760	1,777
Interest Income - securities		188	133	361	263
Investment banking and debt placement fees		149	217	312	379
Deposits		(20)	(16)	(34)	(37)
Unrealized gains (losses) on available for sale securities	[1]	11	13	7	64
Net gain (loss) on cash flow hedging relationships
Net Gains (Losses) Reclassified From OCI Into Income		23	83	87	172
Interest rate | Interest expense – long-term debt | Fair Value Hedging
Net gains (losses) on fair value hedging relationships
Recognized on hedged items		145	(31)	385	173
Recognized on derivatives designated as hedging instruments		(126)	62	(342)	(104)
Net income (expense) recognized on fair value hedges		19	31	43	69
Interest rate | Interest expense – long-term debt | Cash Flow Hedging
Net gain (loss) on cash flow hedging relationships
Realized gains (losses) (pre-tax) reclassified from AOCI into net income		(1)	(1)	(2)	(2)
Net income (expense) recognized on cash flow hedges		(1)	(1)	(2)	(2)
Interest rate | Interest income – loans | Fair Value Hedging
Net gains (losses) on fair value hedging relationships
Recognized on hedged items		0	0	0	0
Recognized on derivatives designated as hedging instruments		0	0	0	0
Net income (expense) recognized on fair value hedges		0	0	0	0
Interest rate | Interest income – loans | Cash Flow Hedging
Net gain (loss) on cash flow hedging relationships
Realized gains (losses) (pre-tax) reclassified from AOCI into net income		19	85	82	173
Net Gains (Losses) Reclassified From OCI Into Income		19	85	82	173
Net income (expense) recognized on cash flow hedges		19	85	82	173
Interest rate | Interest Income - securities | Fair Value Hedging
Net gains (losses) on fair value hedging relationships
Recognized on hedged items		(51)	158	(328)	(107)
Recognized on derivatives designated as hedging instruments		52	(159)	334	108
Net income (expense) recognized on fair value hedges		1	(1)	6	1
Interest rate | Interest Income - securities | Cash Flow Hedging
Net gain (loss) on cash flow hedging relationships
Realized gains (losses) (pre-tax) reclassified from AOCI into net income		0	0	0	0
Net income (expense) recognized on cash flow hedges		0	0	0	0
Interest rate | Investment banking and debt placement fees | Fair Value Hedging
Net gains (losses) on fair value hedging relationships
Recognized on hedged items		0	0	0	0
Recognized on derivatives designated as hedging instruments		0	0	0	0
Net income (expense) recognized on fair value hedges		0	0	0	0
Interest rate | Investment banking and debt placement fees | Cash Flow Hedging
Net gain (loss) on cash flow hedging relationships
Net income (expense) recognized on cash flow hedges		5	1	7	1
Interest rate | Interest expense - deposits | Fair Value Hedging
Net gains (losses) on fair value hedging relationships
Recognized on hedged items			0	0	0
Recognized on derivatives designated as hedging instruments			0	0	0
Net income (expense) recognized on fair value hedges			0	0	0
Interest rate | Interest expense - deposits | Cash Flow Hedging
Net gain (loss) on cash flow hedging relationships
Realized gains (losses) (pre-tax) reclassified from AOCI into net income		0	0	0	0
Net income (expense) recognized on cash flow hedges		0	0	0	0
Interest rate | Other income | Fair Value Hedging
Net gains (losses) on fair value hedging relationships
Recognized on hedged items		0	0	0	0
Recognized on derivatives designated as hedging instruments		0	0	0	0
Net income (expense) recognized on fair value hedges		0	0	0	0
Interest rate | Other income | Cash Flow Hedging
Net gain (loss) on cash flow hedging relationships
Realized gains (losses) (pre-tax) reclassified from AOCI into net income		0	0	0
Net income (expense) recognized on cash flow hedges		0	0	0	0
Interest rate | Investment banking and debt placement fees | Cash Flow Hedging
Net gain (loss) on cash flow hedging relationships
Net Gains (Losses) Reclassified From OCI Into Income		$ 5	$ (1)	$ 7	$ 1

[1] For the three and six months ended June 30, 2022, and June 30, 2021, we had no net securities gains (losses). For the three and six months ended June 30, 2022, and June 30, 2021, we did not have any impairment losses related to securities.