Allowance for Credit Losses - Summary (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025	Dec. 30, 2025
Allowance for Credit Losses
Beginning balance	$ 25,765	$ 24,345	$ 24,345
Gross charge-offs	2,911	2,816
Gross recoveries collected	(595)	(484)
Net charge-offs/(recoveries)	2,316	2,332
Provision for loan losses	2,481	3,193
Other	(2)	2
Ending balance	25,928	25,208	25,765
Allowance for lending-related commitments
Beginning balance	5,071	2,101	2,101
Provision for lending-related commitments	23	125
Other	(3)	0
Ending balance	5,091	2,226	5,071
Total allowance for investment securities	78	118	106
Total allowance for credit losses	31,097	27,552
Allowance for loan losses by impairment methodology
Asset-specific	228	(35)
Portfolio-based	25,700	25,243
Total allowance for loan losses	25,928	25,208	25,765
Loans by impairment methodology
Asset-specific	7,927	6,695
Portfolio-based	1,417,309	1,294,295
Total retained loans	1,425,236	1,300,990	1,408,905
Allowance for lending-related commitments by impairment methodology
Asset-specific	135	135
Portfolio-based	4,956	2,091
Total allowance for lending-related commitments	5,091	2,226	5,071
Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments [Abstract]
Asset-specific	916	793
Portfolio-based	603,407	547,732
Total lending-related commitments	604,323	548,525
Apple Credit Card Portfolio
Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments [Abstract]
Expected period to close				24 months
CIB
Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments [Abstract]
Allowance for credit losses associated with accounts receivable	286	283
Collateral-dependent loans
Allowance for Credit Losses
Net charge-offs/(recoveries)	702	82
Collateral-dependent loans
Loans measured at fair value of collateral less cost to sell	4,294	4,611
Consumer, excluding credit card
Allowance for Credit Losses
Beginning balance	1,920	1,807	1,807
Gross charge-offs	261	287
Gross recoveries collected	(107)	(124)
Net charge-offs/(recoveries)	154	163
Provision for loan losses	23	214
Other	0	0
Ending balance	1,789	1,858	1,920
Allowance for lending-related commitments
Beginning balance	83	82	82
Provision for lending-related commitments	(10)	(10)
Other	0	0
Ending balance	73	72	83
Total allowance for credit losses	1,862	1,930
Allowance for loan losses by impairment methodology
Asset-specific	(623)	(727)
Portfolio-based	2,412	2,585
Total allowance for loan losses	1,789	1,858	1,920
Loans by impairment methodology
Asset-specific	3,403	2,818
Portfolio-based	363,871	370,074
Total retained loans	367,274	372,892	368,741
Allowance for lending-related commitments by impairment methodology
Asset-specific	0	0
Portfolio-based	73	72
Total allowance for lending-related commitments	73	72	83
Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments [Abstract]
Asset-specific	0	0
Portfolio-based	24,367	25,873
Total lending-related commitments	24,367	25,873
Credit card lending-related commitments not permitted to have an allowance for credit losses	21,900	20,300
Consumer, excluding credit card | Collateral-dependent loans
Allowance for Credit Losses
Net charge-offs/(recoveries)	0	(3)
Collateral-dependent loans
Loans measured at fair value of collateral less cost to sell	3,403	2,791
Credit card
Allowance for Credit Losses
Beginning balance	15,557	14,600	14,600
Gross charge-offs	2,486	2,316
Gross recoveries collected	(444)	(334)
Net charge-offs/(recoveries)	2,042	1,982
Provision for loan losses	2,044	2,382
Other	0	0
Ending balance	15,559	15,000	15,557
Allowance for lending-related commitments
Beginning balance	2,200	0	0
Provision for lending-related commitments	0	0
Other	0	0
Ending balance	2,200	0	2,200
Total allowance for credit losses	17,759	15,000
Allowance for loan losses by impairment methodology
Asset-specific	0	0
Portfolio-based	15,559	15,000
Total allowance for loan losses	15,559	15,000	15,557
Loans by impairment methodology
Asset-specific	0	0
Portfolio-based	239,123	223,384
Total retained loans	239,123	223,384
Allowance for lending-related commitments by impairment methodology
Asset-specific	0	0
Portfolio-based	2,200	0
Total allowance for lending-related commitments	2,200	0	2,200
Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments [Abstract]
Asset-specific	0	0
Portfolio-based	23,759	99
Total lending-related commitments	23,759	99
Credit card lending-related commitments not permitted to have an allowance for credit losses	1,200,000	1,000,000
Credit card | Collateral-dependent loans
Allowance for Credit Losses
Net charge-offs/(recoveries)	0	0
Collateral-dependent loans
Loans measured at fair value of collateral less cost to sell	0	0
Wholesale
Allowance for Credit Losses
Beginning balance	8,288	7,938	7,938
Gross charge-offs	164	213
Gross recoveries collected	(44)	(26)
Net charge-offs/(recoveries)	120	187
Provision for loan losses	414	597
Other	(2)	2
Ending balance	8,580	8,350	8,288
Allowance for lending-related commitments
Beginning balance	2,788	2,019	2,019
Provision for lending-related commitments	33	135
Other	(3)	0
Ending balance	2,818	2,154	2,788
Total allowance for credit losses	11,398	10,504
Allowance for loan losses by impairment methodology
Asset-specific	851	692
Portfolio-based	7,729	7,658
Total allowance for loan losses	8,580	8,350	8,288
Loans by impairment methodology
Asset-specific	4,524	3,877
Portfolio-based	814,315	700,837
Total retained loans	818,839	704,714	792,367
Allowance for lending-related commitments by impairment methodology
Asset-specific	135	135
Portfolio-based	2,683	2,019
Total allowance for lending-related commitments	2,818	2,154	2,788
Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments [Abstract]
Asset-specific	916	793
Portfolio-based	555,281	521,760
Total lending-related commitments	556,197	522,553
Credit card lending-related commitments not permitted to have an allowance for credit losses	48,700	26,300
Wholesale | Collateral-dependent loans
Allowance for Credit Losses
Net charge-offs/(recoveries)	702	85
Collateral-dependent loans
Loans measured at fair value of collateral less cost to sell	891	$ 1,820
Credit Card Receivable [Member]
Allowance for Credit Losses
Gross charge-offs	2,486		9,164
Loans by impairment methodology
Total retained loans	239,123		$ 247,797
Credit Card Receivable [Member] | Apple Credit Card Portfolio | Credit Concentration Risk
Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments [Abstract]
Credit exposure for estimated drawn loans	$ 23,000