Business Segments - Business Segment Results (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Securities gains (losses), net	$ 81	$ 17	$ 131	$ 22
Other intangibles	43	42	85	82
Total noninterest expense	3,318	3,153	6,634	6,240
Provision for credit losses	1,737	365	2,730	742
Net income	695	1,828	1,874	3,536
Net (income) loss attributable to noncontrolling interests	(6)	(7)	(14)	(16)
Net income attributable to U.S. Bancorp	689	1,821	1,860	3,520
Corporate and Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net interest income (taxable-equivalent basis)	890	774	1,688	1,552
Noninterest income	340	244	613	452
Total net revenue	1,230	1,018	2,301	2,004
Noninterest expense	411	413	832	820
Other intangibles		1		2
Total noninterest expense	411	414	832	822
Income before provision and income taxes	819	604	1,469	1,182
Provision for credit losses	21	(16)	446	7
Income before income taxes	798	620	1,023	1,175
Income taxes and taxable-equivalent adjustment	200	155	256	294
Net income	598	465	767	881
Net income attributable to U.S. Bancorp	598	465	767	881
Loans	122,950	98,922	113,161	98,800
Other earning assets	3,847	3,883	4,201	3,527
Goodwill	1,647	1,647	1,647	1,647
Other intangible assets	6	9	7	9
Assets	135,504	108,823	125,409	108,063
Noninterest-bearing deposits	38,658	29,061	34,002	29,623
Interest-bearing deposits	95,373	70,740	88,017	70,959
Total deposits	134,031	99,801	122,019	100,582
Total U.S. Bancorp shareholders' equity	17,295	15,436	16,553	15,389
Consumer and Business Banking [Member]
Segment Reporting Information [Line Items]
Net interest income (taxable-equivalent basis)	1,486	1,597	3,029	3,178
Noninterest income	921	567	1,678	1,102
Total net revenue	2,407	2,164	4,707	4,280
Noninterest expense	1,370	1,305	2,684	2,555
Other intangibles	4	5	8	10
Total noninterest expense	1,374	1,310	2,692	2,565
Income before provision and income taxes	1,033	854	2,015	1,715
Provision for credit losses	110	79	233	149
Income before income taxes	923	775	1,782	1,566
Income taxes and taxable-equivalent adjustment	231	194	446	392
Net income	692	581	1,336	1,174
Net income attributable to U.S. Bancorp	692	581	1,336	1,174
Loans	150,206	143,777	148,459	142,804
Other earning assets	6,576	3,333	5,772	2,864
Goodwill	3,475	3,475	3,475	3,475
Other intangible assets	1,935	2,717	2,170	2,799
Assets	167,501	157,445	164,630	156,103
Noninterest-bearing deposits	34,662	27,051	31,265	26,800
Interest-bearing deposits	144,319	128,932	139,041	128,135
Total deposits	178,981	155,983	170,306	154,935
Total U.S. Bancorp shareholders' equity	14,973	15,119	14,952	15,060
Wealth Management and Investment Services [Member]
Segment Reporting Information [Line Items]
Net interest income (taxable-equivalent basis)	256	305	539	598
Noninterest income	463	445	927	875
Total net revenue	719	750	1,466	1,473
Noninterest expense	446	432	879	853
Other intangibles	3	3	6	6
Total noninterest expense	449	435	885	859
Income before provision and income taxes	270	315	581	614
Provision for credit losses	(2)	2	21	(1)
Income before income taxes	272	313	560	615
Income taxes and taxable-equivalent adjustment	68	78	140	154
Net income	204	235	420	461
Net income attributable to U.S. Bancorp	204	235	420	461
Loans	11,194	9,898	10,902	9,858
Other earning assets	285	341	283	293
Goodwill	1,616	1,617	1,616	1,617
Other intangible assets	40	50	42	52
Assets	14,308	13,178	14,129	13,180
Noninterest-bearing deposits	16,298	13,612	14,758	13,459
Interest-bearing deposits	65,300	61,417	67,041	57,805
Total deposits	81,598	75,029	81,799	71,264
Total U.S. Bancorp shareholders' equity	2,478	2,432	2,472	2,437
Payments Services [Member]
Segment Reporting Information [Line Items]
Net interest income (taxable-equivalent basis)	602	585	1,253	1,202
Noninterest income	658	952	1,452	1,806
Total net revenue	1,260	1,537	2,705	3,008
Noninterest expense	722	737	1,448	1,445
Other intangibles	36	33	71	64
Total noninterest expense	758	770	1,519	1,509
Income before provision and income taxes	502	767	1,186	1,499
Provision for credit losses	(31)	295	231	581
Income before income taxes	533	472	955	918
Income taxes and taxable-equivalent adjustment	133	118	239	230
Net income	400	354	716	688
Net income attributable to U.S. Bancorp	400	354	716	688
Loans	30,321	33,277	32,005	32,848
Other earning assets	447	327	423	387
Goodwill	3,101	2,806	3,028	2,810
Other intangible assets	590	533	576	523
Assets	35,473	39,588	37,137	39,112
Noninterest-bearing deposits	3,165	1,221	2,318	1,198
Interest-bearing deposits	117	115	116	113
Total deposits	3,282	1,336	2,434	1,311
Total U.S. Bancorp shareholders' equity	5,876	6,043	5,980	6,009
Treasury and Corporate Support [Member]
Segment Reporting Information [Line Items]
Net interest income (taxable-equivalent basis)	(10)	71	(38)	88
Noninterest income	151	265	338	524
Securities gains (losses), net	81	17	131	22
Total net revenue	222	353	431	634
Noninterest expense	326	224	706	485
Total noninterest expense	326	224	706	485
Income before provision and income taxes	(104)	129	(275)	149
Provision for credit losses	1,639	5	1,799	6
Income before income taxes	(1,743)	124	(2,074)	143
Income taxes and taxable-equivalent adjustment	(544)	(69)	(709)	(189)
Net income	(1,199)	193	(1,365)	332
Net (income) loss attributable to noncontrolling interests	(6)	(7)	(14)	(16)
Net income attributable to U.S. Bancorp	(1,205)	186	(1,379)	316
Loans	3,436	3,344	3,355	3,362
Other earning assets	164,857	129,831	152,360	128,491
Assets	191,520	152,564	178,251	151,063
Noninterest-bearing deposits	2,323	2,151	2,281	2,183
Interest-bearing deposits	3,088	10,932	4,214	10,051
Total deposits	5,411	13,083	6,495	12,234
Total U.S. Bancorp shareholders' equity	11,619	13,408	11,736	13,121
Consolidated Company [Member]
Segment Reporting Information [Line Items]
Net interest income (taxable-equivalent basis)	3,224	3,332	6,471	6,618
Noninterest income	2,533	2,473	5,008	4,759
Securities gains (losses), net	81	17	131	22
Total net revenue	5,838	5,822	11,610	11,399
Noninterest expense	3,275	3,111	6,549	6,158
Other intangibles	43	42	85	82
Total noninterest expense	3,318	3,153	6,634	6,240
Income before provision and income taxes	2,520	2,669	4,976	5,159
Provision for credit losses	1,737	365	2,730	742
Income before income taxes	783	2,304	2,246	4,417
Income taxes and taxable-equivalent adjustment	88	476	372	881
Net income	695	1,828	1,874	3,536
Net (income) loss attributable to noncontrolling interests	(6)	(7)	(14)	(16)
Net income attributable to U.S. Bancorp	689	1,821	1,860	3,520
Loans	318,107	289,218	307,882	287,672
Other earning assets	176,012	137,715	163,039	135,562
Goodwill	9,839	9,545	9,766	9,549
Other intangible assets	2,571	3,309	2,795	3,383
Assets	544,306	471,598	519,556	467,521
Noninterest-bearing deposits	95,106	73,096	84,624	73,263
Interest-bearing deposits	308,197	272,136	298,429	267,063
Total deposits	403,303	345,232	383,053	340,326
Total U.S. Bancorp shareholders' equity	$ 52,241	$ 52,438	$ 51,693	$ 52,016