The remaining balance of senior unsecured debt and subordinated debt which may be issued by the entity.

No definition available.

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

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- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
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-Paragraph 6
-Subparagraph (a)
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-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

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- Definition

Amount of the collateral pledged in support of federal home loan bank advances outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
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- Definition

The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.

+ References

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- Definition

Weighted average interest rate of long-term debt outstanding calculated at point in time.

+ References

No definition available.

+ Details

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- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
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Long-Term Debt (Details) - USD ($) $ in Millions	12 Months Ended
Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term debt	$ 17,129	$ 17,918
Repayments of Long-term Debt	6,471	9,655	$ 4,801
Federal Home Loan advances, collateral pledged	45,000	44,000
Total Loss Absorbing Capacity Loan Agreement [Member]
Debt Instrument [Line Items]
Long-term debt	6,500
MUFG Americas Holdings Corporation
Debt Instrument [Line Items]
Long-term debt	$ 7,622	7,355
MUFG Americas Holdings Corporation \| Senior Debt Obligations [Member]
Debt Instrument [Line Items]
Redeemable debt, percentage of par value	100.00%
MUFG Americas Holdings Corporation \| Senior Debt Obligations [Member] \| Fixed rate 3.50% notes due June 2022
Debt Instrument [Line Items]
Long-term debt	$ 399	$ 398
Debt instrument, stated rate	350.00%	350.00%
MUFG Americas Holdings Corporation \| Senior Debt Obligations [Member] \| Fixed rate 3.00% notes due February 2025
Debt Instrument [Line Items]
Long-term debt	$ 397	$ 397
Debt instrument, stated rate	300.00%	300.00%
MUFG Americas Holdings Corporation \| Senior Debt Obligations [Member] \| Floating Rate Debt Due December 2021 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 0	$ 1,625
Interest rate above variable interest rate (as a percent)	0.00%	358.00%
MUFG Americas Holdings Corporation \| Senior Debt Obligations [Member] \| Floating Rate Debt Due December 2021 [Member] \| LIBOR
Debt Instrument [Line Items]
Interest rate above variable interest rate (as a percent)	0.00%	81.00%
MUFG Americas Holdings Corporation \| Senior Debt Obligations [Member] \| Floating Rate Debt Due December 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 3,250	$ 3,250
Interest rate above variable interest rate (as a percent)	303.00%	367.00%
MUFG Americas Holdings Corporation \| Senior Debt Obligations [Member] \| Floating Rate Debt Due December 2022 [Member] \| LIBOR
Debt Instrument [Line Items]
Interest rate above variable interest rate (as a percent)	90.00%	90.00%
MUFG Americas Holdings Corporation \| Senior Debt Obligations [Member] \| Floating Rate Debt Due December 2022 issued in Q3 2019 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 125	$ 0
Interest rate above variable interest rate (as a percent)	307.00%	0.00%
MUFG Americas Holdings Corporation \| Senior Debt Obligations [Member] \| Floating Rate Debt Due December 2022 issued in Q3 2019 [Member] \| LIBOR
Debt Instrument [Line Items]
Interest rate above variable interest rate (as a percent)	97.00%	0.00%
MUFG Americas Holdings Corporation \| Senior Debt Obligations [Member] \| Floating Rate Debt Due December 2023 LIBOR [Member]
Debt Instrument [Line Items]
Long-term debt	$ 1,625	$ 1,625
Interest rate above variable interest rate (as a percent)	312.00%	376.00%
MUFG Americas Holdings Corporation \| Senior Debt Obligations [Member] \| Floating Rate Debt Due December 2023 LIBOR [Member] \| LIBOR
Debt Instrument [Line Items]
Interest rate above variable interest rate (as a percent)	99.00%	99.00%
MUFG Americas Holdings Corporation \| Senior Debt Obligations [Member] \| Floating Rate Debt Due December 2023 LIBOR Issued in Q42019 [Member] [Member]
Debt Instrument [Line Items]
Long-term debt	$ 1,765	$ 0
Interest rate above variable interest rate (as a percent)	282.00%	0.00%
MUFG Americas Holdings Corporation \| Senior Debt Obligations [Member] \| Floating Rate Debt Due December 2023 LIBOR Issued in Q42019 [Member] [Member] \| LIBOR
Debt Instrument [Line Items]
Interest rate above variable interest rate (as a percent)	94.00%	0.00%
MUFG Americas Holdings Corporation \| Senior Debt Obligations [Member] \| Floating rate subordinated debt due December 2023. This note, which bore interest at 1.38% above 3-month LIBOR, had a rate of 3.07% at December 31, 2017
Debt Instrument [Line Items]
Long-term debt	$ 24	$ 24
Debt instrument, effective interest rate	76.00%	76.00%
MUFG Americas Holdings Corporation \| Senior Debt Obligations [Member] \| Floating rate subordinated debt due December 2023. This note, which bore interest at 1.38% above 3-month LIBOR, had a rate of 3.07% at December 31, 2017 \| Euro Interbank Offered Rate (Euribor) [Member]
Debt Instrument [Line Items]
Interest rate above variable interest rate (as a percent)	76.00%	76.00%
MUFG Americas Holdings Corporation \| Junior subordinated debt payable to trusts \| Floating rate note due September 2036 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 37	$ 36
Debt instrument, effective interest rate	359.00%	449.00%
MUFG Union Bank N.A [Member] \| Senior Debt Obligations [Member] \| Floating Rate Debt Due December 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 300	$ 0
MUFG Union Bank N.A [Member] \| Senior Debt Obligations [Member] \| Floating Rate debt due March 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	300	0
MUFG Union Bank N.A [Member] \| Senior Debt Obligations [Member] \| Variable Rate FHLB advances due October 2020 [Member]
Debt Instrument [Line Items]
Long-term debt	1,100	0
MUFG Union Bank N.A [Member]
Debt Instrument [Line Items]
Long-term debt	8,909	9,632
Amount available for issuance under the bank note program	3,600
MUFG Union Bank N.A [Member] \| Maximum
Debt Instrument [Line Items]
Amount available for issuance under the bank note program	$ 12,000
MUFG Union Bank N.A [Member] \| Senior Debt Obligations [Member] \| Floating Rate Debt Due December 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	226.00%
MUFG Union Bank N.A [Member] \| Senior Debt Obligations [Member] \| Floating Rate Debt Due December 2022 [Member] \| LIBOR
Debt Instrument [Line Items]
Interest rate above variable interest rate (as a percent)	71.00%
MUFG Union Bank N.A [Member] \| Senior Debt Obligations [Member] \| Floating Rate debt due March 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	249.00%
MUFG Union Bank N.A [Member] \| Senior Debt Obligations [Member] \| Floating Rate debt due March 2022 [Member] \| LIBOR
Debt Instrument [Line Items]
Interest rate above variable interest rate (as a percent)	60.00%
MUFG Union Bank N.A [Member] \| Senior Debt Obligations [Member] \| Fixed Rate 2.10 Percent Notes Due December 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 698	0
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	210.00%
MUFG Union Bank N.A [Member] \| Senior Debt Obligations [Member] \| Variable Rate FHLB advances due October 2020 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	190.00%
MUFG Union Bank N.A [Member] \| Senior Debt Obligations [Member] \| Fixed rate 2.25% notes due May 2019
Debt Instrument [Line Items]
Long-term debt	$ 0	$ 498
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate		225.00%
MUFG Union Bank N.A [Member] \| Senior Debt Obligations [Member] \| Fixed Rate 3.15 Percent Notes Due April 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 998	$ 0
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	315.00%
MUFG Union Bank N.A [Member] \| Senior Debt Obligations [Member] \| Fixed Rate Advances Due Between July 2019 and December 2023 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 5,500	$ 9,100
Debt instrument, stated rate	295.00%	266.00%
MUFG Union Bank N.A [Member] \| Other
Debt Instrument [Line Items]
Long-term debt	$ 13	$ 34
Other Subsidiaries, Excluding MUFG Bank, NA [Member]
Debt Instrument [Line Items]
Long-term debt	598	931
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Senior Debt Obligations [Member] \| Floating Rate Borrowings Due Between December 2020 and May 2021 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 250	$ 250
Debt instrument, effective interest rate	194.00%	280.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Senior Debt Obligations [Member] \| Floating Rate Debt Due March 2019 [Member]
Debt Instrument [Line Items]
Debt instrument, effective interest rate		413.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Senior Debt Obligations [Member] \| Floating Rate Debt Due March 2019 [Member] \| Minimum
Debt Instrument [Line Items]
Debt instrument, effective interest rate		0.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Senior Debt Obligations [Member] \| Floating Rate Debt Due March 2019 [Member] \| Maximum
Debt Instrument [Line Items]
Debt instrument, effective interest rate		0.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Senior Debt Obligations [Member] \| Fixed Rate Borrowings Due Between November 2019 and June 2023 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 137	$ 244
Debt instrument, effective interest rate	222.00%	182.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Senior Debt Obligations [Member] \| Fixed Rate Borrowings Due Between November 2019 and June 2023 [Member] \| Minimum
Debt Instrument [Line Items]
Debt instrument, effective interest rate	168.00%	14.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Senior Debt Obligations [Member] \| Fixed Rate Borrowings Due Between November 2019 and June 2023 [Member] \| Maximum
Debt Instrument [Line Items]
Debt instrument, effective interest rate	244.00%	244.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Subordinated Debt \| Floating Rate Debt Due March 2019 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 0	$ 75
Debt instrument, effective interest rate	0.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Subordinated Debt \| Floating Rate Debt Due March 2019 [Member] \| Minimum
Debt Instrument [Line Items]
Debt instrument, effective interest rate	0.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Subordinated Debt \| Floating Rate Debt Due March 2019 [Member] \| Maximum
Debt Instrument [Line Items]
Debt instrument, effective interest rate	0.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Secured Debt \| Fixed rate non-recourse borrowings due December 2026 which had an interest rate of 5.34% at December 31, 2018 and December 31, 2017
Debt Instrument [Line Items]
Long-term debt	$ 29	$ 33
Debt instrument, effective interest rate	534.00%	534.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Secured Debt \| Floating Rate Nonrecourse Debt Due December 2021 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 3	$ 53
Debt instrument, effective interest rate	217.00%	409.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Secured Debt \| Floating Rate Nonrecourse Debt Due December 2021 [Member] \| Minimum
Debt Instrument [Line Items]
Debt instrument, effective interest rate	0.00%	275.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Secured Debt \| Floating Rate Nonrecourse Debt Due December 2021 [Member] \| Maximum
Debt Instrument [Line Items]
Debt instrument, effective interest rate	0.00%	417.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Secured Debt \| Fixed Rate Nonrecourse Debt Due Between March 2020 and July 2023 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 166	$ 187
Long-term Debt, Weighted Average Interest Rate, at Point in Time	307.00%	305.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Secured Debt \| Fixed Rate Nonrecourse Debt Due Between March 2020 and July 2023 [Member] \| Minimum
Debt Instrument [Line Items]
Long-term Debt, Weighted Average Interest Rate, at Point in Time	196.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Secured Debt \| Fixed Rate Nonrecourse Debt Due Between March 2020 and July 2023 [Member] \| Maximum
Debt Instrument [Line Items]
Long-term Debt, Weighted Average Interest Rate, at Point in Time	372.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Secured Debt \| Floating Rate Nonrecourse Borrowings Due Between October 2019 and February 2021 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 13	$ 89
Debt instrument, effective interest rate	393.00%	421.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Secured Debt \| Floating Rate Nonrecourse Borrowings Due Between October 2019 and February 2021 [Member] \| Minimum
Debt Instrument [Line Items]
Debt instrument, effective interest rate	0.00%	417.00%
Other Subsidiaries, Excluding MUFG Bank, NA [Member] \| Secured Debt \| Floating Rate Nonrecourse Borrowings Due Between October 2019 and February 2021 [Member] \| Maximum
Debt Instrument [Line Items]
Debt instrument, effective interest rate	0.00%	448.00%