Business Segments - Business Segment Results (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Noninterest income	$ 2,712	$ 2,614	$ 7,851	$ 7,395
Other intangibles	44	42	129	124
Total noninterest expense	3,371	3,144	10,005	9,384
Provision for credit losses	635	367	3,365	1,109
Net income (loss)	1,586	1,917	3,460	5,453
Net (income) loss attributable to noncontrolling interests	(6)	(9)	(20)	(25)
Net income (loss) attributable to U.S. Bancorp	1,580	1,908	3,440	5,428
Corporate and Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net interest income (taxable-equivalent basis)	808	767	2,498	2,318
Noninterest income	260	212	870	663
Total net revenue	1,068	979	3,368	2,981
Noninterest expense	416	397	1,278	1,225
Other intangibles		1		3
Total noninterest expense	416	398	1,278	1,228
Income before provision and income taxes	652	581	2,090	1,753
Provision for credit losses	90	39	536	46
Income before income taxes	562	542	1,554	1,707
Income taxes and taxable-equivalent adjustment	141	136	389	428
Net income (loss)	421	406	1,165	1,279
Net income (loss) attributable to U.S. Bancorp	421	406	1,165	1,279
Loans	108,158	98,760	111,478	98,785
Other earning assets	4,110	4,016	4,170	3,692
Goodwill	1,647	1,647	1,647	1,647
Other intangible assets	6	8	6	9
Assets	121,014	109,480	123,929	108,539
Noninterest-bearing deposits	43,302	29,058	37,129	29,435
Interest-bearing deposits	82,448	72,087	86,138	71,331
Total deposits	125,750	101,145	123,267	100,766
Total U.S. Bancorp shareholders' equity	16,541	15,580	16,548	15,453
Consumer and Business Banking [Member]
Segment Reporting Information [Line Items]
Net interest income (taxable-equivalent basis)	1,603	1,602	4,629	4,780
Noninterest income	891	666	2,569	1,768
Total net revenue	2,494	2,268	7,198	6,548
Noninterest expense	1,406	1,321	4,145	3,904
Other intangibles	4	5	12	15
Total noninterest expense	1,410	1,326	4,157	3,919
Income before provision and income taxes	1,084	942	3,041	2,629
Provision for credit losses	73	69	306	218
Income before income taxes	1,011	873	2,735	2,411
Income taxes and taxable-equivalent adjustment	253	218	685	602
Net income (loss)	758	655	2,050	1,809
Net income (loss) attributable to U.S. Bancorp	758	655	2,050	1,809
Loans	156,779	145,940	151,256	143,862
Other earning assets	8,206	4,711	6,589	3,486
Goodwill	3,475	3,475	3,508	3,475
Other intangible assets	1,942	2,444	2,095	2,679
Assets	175,760	160,863	168,419	157,708
Noninterest-bearing deposits	39,941	28,590	34,167	27,402
Interest-bearing deposits	149,882	129,587	142,649	128,592
Total deposits	189,823	158,177	176,816	155,994
Total U.S. Bancorp shareholders' equity	15,111	15,229	15,038	15,117
Wealth Management and Investment Services [Member]
Segment Reporting Information [Line Items]
Net interest income (taxable-equivalent basis)	240	295	779	894
Noninterest income	469	454	1,399	1,330
Total net revenue	709	749	2,178	2,224
Noninterest expense	470	439	1,380	1,308
Other intangibles	3	3	9	9
Total noninterest expense	473	442	1,389	1,317
Income before provision and income taxes	236	307	789	907
Provision for credit losses	12	1	33	0
Income before income taxes	224	306	756	907
Income taxes and taxable-equivalent adjustment	56	77	189	227
Net income (loss)	168	229	567	680
Net income (loss) attributable to U.S. Bancorp	168	229	567	680
Loans	11,458	10,264	11,087	9,996
Other earning assets	288	265	285	284
Goodwill	1,618	1,617	1,617	1,617
Other intangible assets	37	47	40	50
Assets	14,562	13,548	14,273	13,306
Noninterest-bearing deposits	16,797	13,613	15,454	13,513
Interest-bearing deposits	62,164	65,997	65,447	60,607
Total deposits	78,961	79,610	80,901	74,120
Total U.S. Bancorp shareholders' equity	2,482	2,456	2,475	2,443
Payments Services [Member]
Segment Reporting Information [Line Items]
Net interest income (taxable-equivalent basis)	634	629	1,888	1,835
Noninterest income	867	957	2,319	2,761
Total net revenue	1,501	1,586	4,207	4,596
Noninterest expense	800	762	2,303	2,231
Other intangibles	37	33	108	97
Total noninterest expense	837	795	2,411	2,328
Income before provision and income taxes	664	791	1,796	2,268
Provision for credit losses	246	260	477	841
Income before income taxes	418	531	1,319	1,427
Income taxes and taxable-equivalent adjustment	105	133	331	357
Net income (loss)	313	398	988	1,070
Net income (loss) attributable to U.S. Bancorp	313	398	988	1,070
Loans	31,168	34,044	31,725	33,251
Other earning assets	5	6	5	6
Goodwill	3,123	2,825	3,027	2,815
Other intangible assets	602	548	584	532
Assets	36,191	39,879	36,497	39,108
Noninterest-bearing deposits	6,886	1,266	3,852	1,221
Interest-bearing deposits	124	117	119	114
Total deposits	7,010	1,383	3,971	1,335
Total U.S. Bancorp shareholders' equity	6,219	6,102	6,056	6,037
Treasury and Corporate Support [Member]
Segment Reporting Information [Line Items]
Net interest income (taxable-equivalent basis)	(33)	13	(71)	97
Noninterest income	225	325	694	873
Total net revenue	192	338	623	970
Noninterest expense	235	183	770	592
Total noninterest expense	235	183	770	592
Income before provision and income taxes	(43)	155	(147)	378
Provision for credit losses	214	(2)	2,013	4
Income before income taxes	(257)	157	(2,160)	374
Income taxes and taxable-equivalent adjustment	(183)	(72)	(850)	(241)
Net income (loss)	(74)	229	(1,310)	615
Net (income) loss attributable to noncontrolling interests	(6)	(9)	(20)	(25)
Net income (loss) attributable to U.S. Bancorp	(80)	220	(1,330)	590
Loans	3,455	3,428	3,389	3,384
Other earning assets	162,477	134,239	156,034	130,680
Assets	189,375	157,684	182,262	153,555
Noninterest-bearing deposits	2,449	2,067	2,333	2,140
Interest-bearing deposits	1,530	7,551	3,310	9,208
Total deposits	3,979	9,618	5,643	11,348
Total U.S. Bancorp shareholders' equity	12,063	13,925	11,819	13,396
Consolidated Company [Member]
Segment Reporting Information [Line Items]
Net interest income (taxable-equivalent basis)	3,252	3,306	9,723	9,924
Noninterest income	2,712	2,614	7,851	7,395
Total net revenue	5,964	5,920	17,574	17,319
Noninterest expense	3,327	3,102	9,876	9,260
Other intangibles	44	42	129	124
Total noninterest expense	3,371	3,144	10,005	9,384
Income before provision and income taxes	2,593	2,776	7,569	7,935
Provision for credit losses	635	367	3,365	1,109
Income before income taxes	1,958	2,409	4,204	6,826
Income taxes and taxable-equivalent adjustment	372	492	744	1,373
Net income (loss)	1,586	1,917	3,460	5,453
Net (income) loss attributable to noncontrolling interests	(6)	(9)	(20)	(25)
Net income (loss) attributable to U.S. Bancorp	1,580	1,908	3,440	5,428
Loans	311,018	292,436	308,935	289,278
Other earning assets	175,086	143,237	167,083	138,148
Goodwill	9,863	9,564	9,799	9,554
Other intangible assets	2,587	3,047	2,725	3,270
Assets	536,902	481,454	525,380	472,216
Noninterest-bearing deposits	109,375	74,594	92,935	73,711
Interest-bearing deposits	296,148	275,339	297,663	269,852
Total deposits	405,523	349,933	390,598	343,563
Total U.S. Bancorp shareholders' equity	$ 52,416	$ 53,292	$ 51,936	$ 52,446