Fair Value, Assets and Liabilities Measured on a Recurring Basis Level 3 Valuation Techniques and Significant Unobservable Inputs (Details) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2019 USD ($) $ / loan	Dec. 31, 2018 USD ($) $ / loan
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Mortgage servicing rights	$ 12,096	$ 14,649
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	265,983	269,912
Securities of U.S. states and political subdivisions [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	45,095	49,264
Corporate debt securities [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	6,230	6,271
Collateralized loan obligations [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	32,995	35,343
Collateralized debt obligations [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	649	800
Recurring [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Mortgage loans held for sale, carried at fair value	16,343	11,771
Loans	202	244
Mortgage servicing rights	12,096	14,649
Fair Value Disclosures, Textual [Abstract]
Total assets recorded at fair value	415,062	408,360
Total liabilities recorded at fair value	24,356	28,221
Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Mortgage loans held for sale, carried at fair value	1,115	997
Loans	202	244
Mortgage servicing rights	12,096	14,649
Total insignificant level 3 assets, net of liabilities	26	93
Assets, fair value disclosure, net of liabilities	22,628	23,771
Fair Value Disclosures, Textual [Abstract]
Total assets recorded at fair value	24,900	25,300
Total liabilities recorded at fair value	2,304	1,551
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Market comparable pricing [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Mortgage loans held for sale, carried at fair value	14	15
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Mortgage loans held for sale, carried at fair value	1,101	982
Loans	202	244
Mortgage servicing rights	$ 12,096	$ 14,649
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Market comparable pricing [Member] | Measurement Input, Comparability Adjustment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Mortgage Loans Held for Sale, Measurement Input	(0.563)	(0.563)
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Mortgage Loans Held for Sale, Measurement Input	0.030	0.011
Loans, Measurement Input	0.039	0.034
Servicing Asset, Measurement Input	0.065	0.071
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Default Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Mortgage Loans Held for Sale, Measurement Input	0.000	0.000
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Loss Severity [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Mortgage Loans Held for Sale, Measurement Input	0.000	0
Loans, Measurement Input	0.000	0.000
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Cost of Service Per Loan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Servicing Asset, Measurement Input | $ / loan	63	62
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Prepayment Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Mortgage Loans Held for Sale, Measurement Input	0.043	0.032
Loans, Measurement Input	0.044	0.029
Servicing Asset, Measurement Input	0.106	0.090
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Market comparable pricing [Member] | Measurement Input, Comparability Adjustment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Mortgage Loans Held for Sale, Measurement Input	(0.250)	(0.063)
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Mortgage Loans Held for Sale, Measurement Input	0.063	0.066
Loans, Measurement Input	0.044	0.064
Servicing Asset, Measurement Input	0.132	0.153
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Default Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Mortgage Loans Held for Sale, Measurement Input	0.184	0.156
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Loss Severity [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Mortgage Loans Held for Sale, Measurement Input	0.464	0.433
Loans, Measurement Input	0.348	0.348
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Cost of Service Per Loan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Servicing Asset, Measurement Input | $ / loan	482	507
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Prepayment Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Mortgage Loans Held for Sale, Measurement Input	0.144	0.134
Loans, Measurement Input	1.000	1.000
Servicing Asset, Measurement Input	0.246	0.235
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Market comparable pricing [Member] | Measurement Input, Comparability Adjustment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Mortgage Loans Held for Sale, Measurement Input	(0.409)	(0.363)
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Mortgage Loans Held for Sale, Measurement Input	0.046	0.055
Loans, Measurement Input	0.041	0.042
Servicing Asset, Measurement Input	0.074	0.081
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Default Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Mortgage Loans Held for Sale, Measurement Input	0.008	0.008
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Loss Severity [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Mortgage Loans Held for Sale, Measurement Input	0.250	0.234
Loans, Measurement Input	0.120	0.102
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Cost of Service Per Loan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Servicing Asset, Measurement Input | $ / loan	104	106
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Prepayment Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Mortgage Loans Held for Sale, Measurement Input	0.061	0.046
Loans, Measurement Input	0.856	0.872
Servicing Asset, Measurement Input	0.122	0.099
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest rate contract [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Net derivative assets and liabilities	$ 111	$ (35)
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest rate contract [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Default Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.000	0.000
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest rate contract [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Loss Severity [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.500	0.500
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest rate contract [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Prepayment Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.028	0.028
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest rate contract [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Default Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.050	0.050
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest rate contract [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Loss Severity [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.500	0.500
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest rate contract [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Prepayment Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.250	0.250
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest rate contract [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Default Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.020	0.020
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest rate contract [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Loss Severity [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.500	0.500
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest rate contract [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Prepayment Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.153	0.138
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Derivative Loan Commitments [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Net derivative assets and liabilities	$ 94	$ 60
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Derivative Loan Commitments [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Fall-out Factor [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.010	0.010
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Derivative Loan Commitments [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Initial-value Servicing [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	(0.00405)	(0.00366)
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Derivative Loan Commitments [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Fall-out Factor [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.990	0.990
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Derivative Loan Commitments [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Initial-value Servicing [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.00671	0.00917
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Derivative Loan Commitments [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Fall-out Factor [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.195	0.194
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Derivative Loan Commitments [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Initial-value Servicing [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.00123	0.00185
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity contract [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Net derivative assets and liabilities	$ 146	$ 104
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity contract [Member] | Option model [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Net derivative assets and liabilities	$ (374)	$ (121)
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity contract [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Weighted Average Life [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative, Term of Contract	1 year	1 year
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity contract [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Conversion Factor [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	(0.089)	(0.093)
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity contract [Member] | Minimum [Member] | Option model [Member] | Measurement Input, Correlation Factor [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	(0.770)	(0.770)
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity contract [Member] | Minimum [Member] | Option model [Member] | Measurement Input, Price Volatility [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.065	0.065
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity contract [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Weighted Average Life [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative, Term of Contract	3 years 6 months	3 years
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity contract [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Conversion Factor [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.000	0.000
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity contract [Member] | Maximum [Member] | Option model [Member] | Measurement Input, Correlation Factor [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.985	0.990
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity contract [Member] | Maximum [Member] | Option model [Member] | Measurement Input, Price Volatility [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	1.052	1.000
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity contract [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Weighted Average Life [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative, Term of Contract	2 years	1 year 9 months 18 days
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity contract [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Conversion Factor [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	(0.083)	(0.078)
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity contract [Member] | Weighted Average [Member] | Option model [Member] | Measurement Input, Correlation Factor [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.639	0.216
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity contract [Member] | Weighted Average [Member] | Option model [Member] | Measurement Input, Price Volatility [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.241	0.218
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Credit contract [Member] | Market comparable pricing [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Net derivative assets and liabilities	$ 2	$ 3
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Credit contract [Member] | Option model [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Net derivative assets and liabilities	$ 43	$ 32
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Credit contract [Member] | Minimum [Member] | Market comparable pricing [Member] | Measurement Input, Comparability Adjustment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	(0.483)	(0.155)
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Credit contract [Member] | Minimum [Member] | Option model [Member] | Measurement Input, Credit Spread [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.001	0.009
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Credit contract [Member] | Minimum [Member] | Option model [Member] | Measurement Input, Loss Severity [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.130	0.130
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Credit contract [Member] | Maximum [Member] | Market comparable pricing [Member] | Measurement Input, Comparability Adjustment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.296	0.400
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Credit contract [Member] | Maximum [Member] | Option model [Member] | Measurement Input, Credit Spread [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.214	0.215
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Credit contract [Member] | Maximum [Member] | Option model [Member] | Measurement Input, Loss Severity [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.600	0.600
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Credit contract [Member] | Weighted Average [Member] | Market comparable pricing [Member] | Measurement Input, Comparability Adjustment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	(0.069)	0.035
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Credit contract [Member] | Weighted Average [Member] | Option model [Member] | Measurement Input, Credit Spread [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.009	0.013
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Credit contract [Member] | Weighted Average [Member] | Option model [Member] | Measurement Input, Loss Severity [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Derivative Asset (Liability) Net, Measurement Input	0.456	0.452
Recurring [Member] | Non modified loans [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Cost of Service Per Loan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Servicing Asset, Measurement Input | $ / loan	63	62
Recurring [Member] | Non modified loans [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Cost of Service Per Loan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Servicing Asset, Measurement Input | $ / loan	208	204
Recurring [Member] | Debt securities [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	$ 265,983	$ 269,912
Recurring [Member] | Debt securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	1,805	2,044
Recurring [Member] | Securities of U.S. states and political subdivisions [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	45,095	49,264
Recurring [Member] | Securities of U.S. states and political subdivisions [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	391	444
Recurring [Member] | Government, healthcare and other revenue bonds [Member] | Fair Value, Inputs, Level 3 [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Debt securities, trading and available-for-sale	353	404
Recurring [Member] | Government, healthcare and other revenue bonds [Member] | Fair Value, Inputs, Level 3 [Member] | Valuation Technique, Vendor Pricing [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Debt securities, trading and available-for-sale	$ 38	$ 43
Recurring [Member] | Government, healthcare and other revenue bonds [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	0.015	0.021
Recurring [Member] | Government, healthcare and other revenue bonds [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	0.062	0.064
Recurring [Member] | Government, healthcare and other revenue bonds [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	0.030	0.034
Recurring [Member] | Corporate debt securities [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	$ 6,230	$ 6,271
Recurring [Member] | Corporate debt securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	383	370
Recurring [Member] | Corporate debt securities [Member] | Fair Value, Inputs, Level 3 [Member] | Market comparable pricing [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Debt securities, trading and available-for-sale	66	56
Recurring [Member] | Corporate debt securities [Member] | Fair Value, Inputs, Level 3 [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Debt securities, trading and available-for-sale	232	220
Recurring [Member] | Corporate debt securities [Member] | Fair Value, Inputs, Level 3 [Member] | Valuation Technique, Vendor Pricing [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Debt securities, trading and available-for-sale	$ 129	$ 128
Recurring [Member] | Corporate debt securities [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Market comparable pricing [Member] | Measurement Input, Comparability Adjustment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	(0.140)	(0.113)
Recurring [Member] | Corporate debt securities [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	0.020	0.040
Recurring [Member] | Corporate debt securities [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Market comparable pricing [Member] | Measurement Input, Comparability Adjustment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	0.144	0.166
Recurring [Member] | Corporate debt securities [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	0.149	0.117
Recurring [Member] | Corporate debt securities [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Market comparable pricing [Member] | Measurement Input, Comparability Adjustment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	(0.028)	(0.014)
Recurring [Member] | Corporate debt securities [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	0.085	0.085
Recurring [Member] | Collateralized loan obligations [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	$ 32,995	$ 35,343
Recurring [Member] | Collateralized loan obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	649	800
Recurring [Member] | Collateralized loan obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Market comparable pricing [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Debt securities, trading and available-for-sale	249	298
Recurring [Member] | Collateralized loan obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Valuation Technique, Vendor Pricing [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Debt securities, trading and available-for-sale	$ 649	$ 739
Recurring [Member] | Collateralized loan obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Market comparable pricing [Member] | Measurement Input, Comparability Adjustment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	(0.113)	(0.135)
Recurring [Member] | Collateralized loan obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Market comparable pricing [Member] | Measurement Input, Comparability Adjustment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	0.200	0.221
Recurring [Member] | Collateralized loan obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Market comparable pricing [Member] | Measurement Input, Comparability Adjustment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	0.017	0.032
Recurring [Member] | Asset-backed securities [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	$ 5,036	$ 5,482
Recurring [Member] | Asset-backed securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	341	389
Recurring [Member] | Other asset-backed securities [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	4,133	4,445
Recurring [Member] | Other asset-backed securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	341	389
Recurring [Member] | Diversified payment rights [Member] | Fair Value, Inputs, Level 3 [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Debt securities, trading and available-for-sale	$ 132	$ 171
Recurring [Member] | Diversified payment rights [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	0.025	0.034
Recurring [Member] | Diversified payment rights [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	0.049	0.062
Recurring [Member] | Diversified payment rights [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	0.034	0.044
Recurring [Member] | Other commercial and consumer [Member] | Fair Value, Inputs, Level 3 [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Debt securities, trading and available-for-sale	$ 194	$ 198
Recurring [Member] | Other commercial and consumer [Member] | Fair Value, Inputs, Level 3 [Member] | Valuation Technique, Vendor Pricing [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Debt securities, trading and available-for-sale	$ 15	$ 20
Recurring [Member] | Other commercial and consumer [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	0.039	0.046
Recurring [Member] | Other commercial and consumer [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Discounted cash flow [Member] | Measurement Input, Weighted Average Life [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Trading and Available-for-sale, Term	1 year 3 months 18 days	1 year 1 month 6 days
Recurring [Member] | Other commercial and consumer [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	0.048	0.052
Recurring [Member] | Other commercial and consumer [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Discounted cash flow [Member] | Measurement Input, Weighted Average Life [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Trading and Available-for-sale, Term	1 year 10 months 24 days	1 year 6 months
Recurring [Member] | Other commercial and consumer [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Available-for-sale, Measurement Input	0.040	0.047
Recurring [Member] | Other commercial and consumer [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Discounted cash flow [Member] | Measurement Input, Weighted Average Life [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Debt Securities, Trading and Available-for-sale, Term	1 year 9 months 18 days	1 year 1 month 6 days
Recurring [Member] | Collateralized debt obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Disclosures, Textual [Abstract]
Available-for-sale, at fair value	$ 649	$ 800
Recurring [Member] | Nonmarketable equity securities [Member] | Fair Value, Inputs, Level 3 [Member] | Market comparable pricing [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Nonmarketable equity securities	$ 7,110	$ 5,468
Recurring [Member] | Nonmarketable equity securities [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] | Market comparable pricing [Member] | Measurement Input, Comparability Adjustment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Nonmarketable equity securities, measurement input	(21.70%)	(20.60%)
Recurring [Member] | Nonmarketable equity securities [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] | Market comparable pricing [Member] | Measurement Input, Comparability Adjustment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Nonmarketable equity securities, measurement input	(6.30%)	(4.30%)
Recurring [Member] | Nonmarketable equity securities [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] | Market comparable pricing [Member] | Measurement Input, Comparability Adjustment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Abstract]
Nonmarketable equity securities, measurement input	(16.60%)	(15.80%)