Basis of Presentation - Line of Business Financial Performance (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 3,226	$ 3,100	$ 6,423	$ 6,130
Net interest income (taxable-equivalent basis), Percent change	4.10%		4.80%
Noninterest income	$ 2,404	2,339	$ 4,671	4,569
Noninterest income, Percent change	2.80%		2.20%
Securities gains (losses), net	$ 10	9	$ 15	38
Securities gains (losses), net, Percent change	11.10%		(60.50%)
Total net revenue	$ 5,640	5,448	$ 11,109	10,737
Total net revenue, Percent change	3.50%		3.50%
Noninterest expense, Percent change	3.50%		4.40%
Other intangibles, Percent change	(7.00%)		(9.20%)
Total noninterest expense, Percent change	3.40%		4.20%
Income before provision and income taxes, Percent change	3.70%		2.60%
Provision for credit losses, Percent change	(6.60%)		(3.90%)
Income before income taxes, Percent change	5.40%		3.70%
Income taxes and taxable-equivalent adjustment, Percent change	(21.90%)		(25.20%)
Net income, Percent change	16.30%		14.70%
Net (income) loss attributable to noncontrolling interests, Percent change	33.30%		40.00%
Net income attributable to U.S. Bancorp, Percent change	16.70%		15.20%
Noninterest expense	$ 3,045	2,941	$ 6,061	5,806
Other intangibles	40	43	79	87
Total noninterest expense	3,085	2,984	6,140	5,893
Income before provision and income taxes	2,555	2,464	4,969	4,844
Provision for credit losses	327	350	668	695
Income before income taxes	2,228	2,114	4,301	4,149
Income taxes and taxable-equivalent adjustment	470	602	861	1,151
Net income	1,758	1,512	3,440	2,998
Net (income) loss attributable to noncontrolling interests	(8)	(12)	(15)	(25)
Net income attributable to U.S. Bancorp	1,750	1,500	3,425	2,973
Average Balance Sheet
Commercial	$ 98,353	95,638	$ 97,912	94,694
Commercial, Percent change	2.80%		3.40%
Commercial real estate	$ 39,857	42,549	$ 40,110	42,852
Commercial real estate, Percent change	(6.30%)		(6.40%)
Residential mortgages	$ 60,834	58,544	$ 60,505	58,224
Residential mortgages, Percent change	3.90%		3.90%
Credit card	$ 21,220	20,631	$ 21,252	20,737
Credit card, Percent change	2.90%		2.50%
Other retail	$ 55,463	54,627	$ 56,253	54,208
Other retail, Percent change	1.50%		3.80%
Total loans, excluding covered loans	$ 275,727	271,989	$ 276,032	270,715
Total loans, excluding covered loans, Percent change	1.40%		2.00%
Covered loans	$ 2,897	3,539	$ 2,972	3,635
Covered loans, Percent change	(18.10%)		(18.20%)
Total loans	$ 278,624	275,528	$ 279,004	274,350
Total loans, Percent change	1.10%		1.70%
Goodwill, Percent change	0.90%		0.90%
Other intangible assets, Percent change	5.10%		3.20%
Assets, Percent change	1.90%		2.40%
Noninterest-bearing deposits, Percent change	(4.50%)		(3.10%)
Interest checking, Percent change	3.90%		5.50%
Savings products, Percent change	(1.30%)		(1.80%)
Time deposits, Percent change	21.50%		21.10%
Total deposits, Percent change	1.10%		1.50%
Total U.S. Bancorp shareholders' equity, Percent change	2.20%		2.00%
Goodwill	$ 9,433	9,353	$ 9,436	9,350
Other intangible assets	3,401	3,235	3,375	3,270
Assets	454,489	446,105	454,389	443,721
Noninterest-bearing deposits	78,987	82,710	79,234	81,729
Interest checking	69,918	67,290	70,136	66,490
Savings products	148,402	150,301	148,080	150,832
Time deposits	37,515	30,871	37,252	30,759
Total deposits	334,822	331,172	334,702	329,810
Total U.S. Bancorp shareholders' equity	49,322	48,273	49,075	48,099
Corporate and Commercial Banking [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	725	725	$ 1,447	1,433
Net interest income (taxable-equivalent basis), Percent change			1.00%
Noninterest income	$ 223	242	$ 431	490
Noninterest income, Percent change	(7.90%)		(12.00%)
Securities gains (losses), net				(3)
Total net revenue	$ 948	967	$ 1,878	1,920
Total net revenue, Percent change	(2.00%)		(2.20%)
Noninterest expense, Percent change	2.50%		2.40%
Total noninterest expense, Percent change	2.50%		2.40%
Income before provision and income taxes, Percent change	(5.10%)		(5.40%)
Provision for credit losses, Percent change	33.30%		(88.90%)
Income before income taxes, Percent change	(5.90%)		(4.00%)
Income taxes and taxable-equivalent adjustment, Percent change	(35.30%)		(34.10%)
Net income, Percent change	10.90%		13.20%
Net income attributable to U.S. Bancorp, Percent change	10.90%		13.20%
Noninterest expense	$ 403	393	$ 797	778
Other intangibles	1	1	2	2
Total noninterest expense	404	394	799	780
Income before provision and income taxes	544	573	1,079	1,140
Provision for credit losses	(12)	(18)	2	18
Income before income taxes	556	591	1,077	1,122
Income taxes and taxable-equivalent adjustment	139	215	269	408
Net income	417	376	808	714
Net income attributable to U.S. Bancorp	417	376	808	714
Average Balance Sheet
Commercial	$ 74,813	73,399	$ 74,813	72,912
Commercial, Percent change	1.90%		2.60%
Commercial real estate	$ 18,697	20,820	$ 18,915	21,062
Commercial real estate, Percent change	(10.20%)		(10.20%)
Residential mortgages	$ 6	6	$ 6	7
Residential mortgages, Percent change			(14.30%)
Other retail	1		$ 1
Total loans, excluding covered loans	$ 93,517	94,225	$ 93,735	93,981
Total loans, excluding covered loans, Percent change	(0.80%)		(0.30%)
Total loans	$ 93,517	94,225	$ 93,735	93,981
Total loans, Percent change	(0.80%)		(0.30%)
Other intangible assets, Percent change	(21.40%)		(21.40%)
Assets, Percent change	(0.50%)		(0.10%)
Noninterest-bearing deposits, Percent change	(8.40%)		(7.60%)
Interest checking, Percent change			1.30%
Savings products, Percent change	(7.30%)		(8.70%)
Time deposits, Percent change	35.50%		34.00%
Total deposits, Percent change	(1.50%)		(2.20%)
Total U.S. Bancorp shareholders' equity, Percent change	5.80%		6.70%
Goodwill	$ 1,647	1,647	$ 1,647	1,647
Other intangible assets	11	14	11	14
Assets	102,585	103,105	102,615	102,712
Noninterest-bearing deposits	33,379	36,438	33,893	36,697
Interest checking	9,545	9,545	9,519	9,401
Savings products	42,448	45,780	43,188	47,291
Time deposits	18,370	13,556	17,452	13,023
Total deposits	103,742	105,319	104,052	106,412
Total U.S. Bancorp shareholders' equity	10,500	9,921	10,459	9,801
Consumer and Business Banking [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 1,539	1,466	$ 3,069	2,894
Net interest income (taxable-equivalent basis), Percent change	5.00%		6.00%
Noninterest income	$ 590	606	$ 1,160	1,177
Noninterest income, Percent change	(2.60%)		(1.40%)
Total net revenue	$ 2,129	2,072	$ 4,229	4,071
Total net revenue, Percent change	2.80%		3.90%
Noninterest expense, Percent change	4.00%		3.70%
Total noninterest expense, Percent change	4.00%		3.60%
Income before provision and income taxes, Percent change	0.60%		4.30%
Provision for credit losses, Percent change	(33.30%)		(25.20%)
Income before income taxes, Percent change	5.10%		7.80%
Income taxes and taxable-equivalent adjustment, Percent change	(27.50%)		(25.90%)
Net income, Percent change	23.80%		27.00%
Net income attributable to U.S. Bancorp, Percent change	23.80%		27.00%
Noninterest expense	$ 1,347	1,295	$ 2,668	2,574
Other intangibles	7	7	14	14
Total noninterest expense	1,354	1,302	2,682	2,588
Income before provision and income taxes	775	770	1,547	1,483
Provision for credit losses	60	90	116	155
Income before income taxes	715	680	1,431	1,328
Income taxes and taxable-equivalent adjustment	179	247	358	483
Net income	536	433	1,073	845
Net income attributable to U.S. Bancorp	536	433	1,073	845
Average Balance Sheet
Commercial	$ 10,028	10,227	$ 9,931	10,069
Commercial, Percent change	(1.90%)		(1.40%)
Commercial real estate	$ 18,172	18,503	$ 18,194	18,527
Commercial real estate, Percent change	(1.80%)		(1.80%)
Residential mortgages	$ 57,591	55,778	$ 57,327	55,510
Residential mortgages, Percent change	3.30%		3.30%
Other retail	$ 53,409	52,479	$ 54,203	52,083
Other retail, Percent change	1.80%		4.10%
Total loans, excluding covered loans	$ 139,200	136,987	$ 139,655	136,189
Total loans, excluding covered loans, Percent change	1.60%		2.50%
Covered loans	$ 2,897	3,533	$ 2,972	3,625
Covered loans, Percent change	(18.00%)		(18.00%)
Total loans	$ 142,097	140,520	$ 142,627	139,814
Total loans, Percent change	1.10%		2.00%
Other intangible assets, Percent change	7.40%		5.60%
Assets, Percent change	1.70%		2.10%
Noninterest-bearing deposits, Percent change	1.00%		1.20%
Interest checking, Percent change	6.90%		6.80%
Savings products, Percent change	2.60%		2.70%
Time deposits, Percent change	(0.20%)		(2.50%)
Total deposits, Percent change	3.40%		3.30%
Total U.S. Bancorp shareholders' equity, Percent change	7.10%		6.60%
Goodwill	$ 3,681	3,681	$ 3,681	3,681
Other intangible assets	2,932	2,730	2,902	2,749
Assets	156,803	154,221	157,164	153,932
Noninterest-bearing deposits	27,565	27,287	27,456	27,122
Interest checking	50,599	47,332	49,988	46,809
Savings products	62,203	60,645	61,867	60,244
Time deposits	12,779	12,804	12,678	13,003
Total deposits	153,146	148,068	151,989	147,178
Total U.S. Bancorp shareholders' equity	12,244	11,435	12,232	11,478
Wealth Management and Investment Services [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 290	260	$ 572	503
Net interest income (taxable-equivalent basis), Percent change	11.50%		13.70%
Noninterest income	$ 430	412	$ 861	810
Noninterest income, Percent change	4.40%		6.30%
Total net revenue	$ 720	672	$ 1,433	1,313
Total net revenue, Percent change	7.10%		9.10%
Noninterest expense, Percent change	14.20%		10.00%
Other intangibles, Percent change	(20.00%)		(20.00%)
Total noninterest expense, Percent change	13.70%		9.60%
Income before provision and income taxes, Percent change	(2.20%)		8.40%
Income before income taxes, Percent change	(2.50%)		8.20%
Income taxes and taxable-equivalent adjustment, Percent change	(33.30%)		(25.70%)
Net income, Percent change	15.20%		27.60%
Net income attributable to U.S. Bancorp, Percent change	15.20%		27.60%
Noninterest expense	$ 443	388	$ 857	779
Other intangibles	4	5	8	10
Total noninterest expense	447	393	865	789
Income before provision and income taxes	273	279	568	524
Provision for credit losses		(1)	1
Income before income taxes	273	280	567	524
Income taxes and taxable-equivalent adjustment	68	102	142	191
Net income	205	178	425	333
Net income attributable to U.S. Bancorp	205	178	425	333
Average Balance Sheet
Commercial	$ 3,737	3,375	$ 3,699	3,283
Commercial, Percent change	10.70%		12.70%
Commercial real estate	$ 519	507	$ 515	510
Commercial real estate, Percent change	2.40%		1.00%
Residential mortgages	$ 3,232	2,752	$ 3,167	2,699
Residential mortgages, Percent change	17.40%		17.30%
Other retail	$ 1,645	1,684	$ 1,633	1,653
Other retail, Percent change	(2.30%)		(1.20%)
Total loans, excluding covered loans	$ 9,133	8,318	$ 9,014	8,145
Total loans, excluding covered loans, Percent change	9.80%		10.70%
Total loans	$ 9,133	8,318	$ 9,014	8,145
Total loans, Percent change	9.80%		10.70%
Goodwill, Percent change	0.10%		0.10%
Other intangible assets, Percent change	(20.50%)		(20.00%)
Assets, Percent change	5.90%		4.80%
Noninterest-bearing deposits, Percent change	(7.40%)		(2.30%)
Interest checking, Percent change	(6.00%)		3.50%
Savings products, Percent change	(0.60%)		(0.80%)
Time deposits, Percent change	(9.30%)		(16.10%)
Total deposits, Percent change	(3.30%)		(1.50%)
Total U.S. Bancorp shareholders' equity, Percent change	2.50%		1.20%
Goodwill	$ 1,569	1,567	$ 1,569	1,567
Other intangible assets	66	83	68	85
Assets	12,107	11,437	11,997	11,444
Noninterest-bearing deposits	14,767	15,952	14,558	14,905
Interest checking	9,737	10,362	10,590	10,234
Savings products	43,084	43,333	42,385	42,748
Time deposits	3,887	4,285	3,792	4,519
Total deposits	71,475	73,932	71,325	72,406
Total U.S. Bancorp shareholders' equity	2,424	2,365	2,412	2,383
Payment Services [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 592	581	$ 1,202	1,177
Net interest income (taxable-equivalent basis), Percent change	1.90%		2.10%
Noninterest income	$ 903	850	$ 1,751	1,648
Noninterest income, Percent change	6.20%		6.30%
Total net revenue	$ 1,495	1,431	$ 2,953	2,825
Total net revenue, Percent change	4.50%		4.50%
Noninterest expense, Percent change	6.00%		7.60%
Other intangibles, Percent change	(6.70%)		(9.80%)
Total noninterest expense, Percent change	5.50%		6.90%
Income before provision and income taxes, Percent change	3.50%		2.30%
Provision for credit losses, Percent change	(0.70%)		5.50%
Income before income taxes, Percent change	6.20%		0.50%
Income taxes and taxable-equivalent adjustment, Percent change	(27.30%)		(31.00%)
Net income, Percent change	25.30%		18.50%
Net income attributable to U.S. Bancorp, Percent change	28.00%		21.20%
Noninterest expense	$ 705	665	$ 1,408	1,308
Other intangibles	28	30	55	61
Total noninterest expense	733	695	1,463	1,369
Income before provision and income taxes	762	736	1,490	1,456
Provision for credit losses	281	283	553	524
Income before income taxes	481	453	937	932
Income taxes and taxable-equivalent adjustment	120	165	234	339
Net income	361	288	703	593
Net (income) loss attributable to noncontrolling interests		(6)		(13)
Net income attributable to U.S. Bancorp	361	282	703	580
Average Balance Sheet
Commercial	$ 8,963	7,975	$ 8,660	7,794
Commercial, Percent change	12.40%		11.10%
Credit card	$ 21,220	20,631	$ 21,252	20,737
Credit card, Percent change	2.90%		2.50%
Other retail	$ 408	464	$ 416	472
Other retail, Percent change	(12.10%)		(11.90%)
Total loans, excluding covered loans	$ 30,591	29,070	$ 30,328	29,003
Total loans, excluding covered loans, Percent change	5.20%		4.60%
Total loans	$ 30,591	29,070	$ 30,328	29,003
Total loans, Percent change	5.20%		4.60%
Goodwill, Percent change	3.20%		3.40%
Other intangible assets, Percent change	(3.90%)		(6.60%)
Assets, Percent change	5.10%		4.90%
Noninterest-bearing deposits, Percent change	6.90%		8.50%
Savings products, Percent change	3.90%		4.00%
Time deposits, Percent change	50.00%		50.00%
Total deposits, Percent change	6.70%		8.20%
Total U.S. Bancorp shareholders' equity, Percent change	6.00%		4.70%
Goodwill	$ 2,536	2,458	$ 2,539	2,455
Other intangible assets	392	408	394	422
Assets	36,552	34,779	36,364	34,672
Noninterest-bearing deposits	1,085	1,015	1,106	1,019
Savings products	106	102	105	101
Time deposits	3	2	3	2
Total deposits	1,194	1,119	1,214	1,122
Total U.S. Bancorp shareholders' equity	6,602	6,228	6,612	6,316
Treasury and Corporate Support [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 80	68	$ 133	123
Net interest income (taxable-equivalent basis), Percent change	17.60%		8.10%
Noninterest income	$ 258	229	$ 468	444
Noninterest income, Percent change	12.70%		5.40%
Securities gains (losses), net	$ 10	9	$ 15	41
Securities gains (losses), net, Percent change	11.10%		(63.40%)
Total net revenue	$ 348	306	$ 616	608
Total net revenue, Percent change	13.70%		1.30%
Noninterest expense, Percent change	(26.50%)		(9.80%)
Total noninterest expense, Percent change	(26.50%)		(9.80%)
Income before provision and income taxes, Percent change	89.60%		18.30%
Provision for credit losses, Percent change	50.00%
Income before income taxes, Percent change	84.50%		18.90%
Income taxes and taxable-equivalent adjustment, Percent change	71.70%		47.40%
Net income, Percent change	0.80%		(16.00%)
Net (income) loss attributable to noncontrolling interests, Percent change	(33.30%)		(25.00%)
Net income attributable to U.S. Bancorp, Percent change			(17.00%)
Noninterest expense	$ 147	200	$ 331	367
Total noninterest expense	147	200	331	367
Income before provision and income taxes	201	106	285	241
Provision for credit losses	(2)	(4)	(4)	(2)
Income before income taxes	203	110	289	243
Income taxes and taxable-equivalent adjustment	(36)	(127)	(142)	(270)
Net income	239	237	431	513
Net (income) loss attributable to noncontrolling interests	(8)	(6)	(15)	(12)
Net income attributable to U.S. Bancorp	231	231	416	501
Average Balance Sheet
Commercial	$ 812	662	$ 809	636
Commercial, Percent change	22.70%		27.20%
Commercial real estate	$ 2,469	2,719	$ 2,486	2,753
Commercial real estate, Percent change	(9.20%)		(9.70%)
Residential mortgages	$ 5	8	$ 5	8
Residential mortgages, Percent change	(37.50%)		(37.50%)
Total loans, excluding covered loans	$ 3,286	3,389	$ 3,300	3,397
Total loans, excluding covered loans, Percent change	(3.00%)		(2.90%)
Covered loans		6		10
Total loans	$ 3,286	3,395	$ 3,300	3,407
Total loans, Percent change	(3.20%)		(3.10%)
Assets, Percent change	2.70%		3.80%
Noninterest-bearing deposits, Percent change	8.60%		11.80%
Interest checking, Percent change	(27.50%)		(15.20%)
Savings products, Percent change	27.20%		19.40%
Total deposits, Percent change	92.60%
Total U.S. Bancorp shareholders' equity, Percent change	(4.20%)		(4.20%)
Assets	$ 146,442	142,563	$ 146,249	140,961
Noninterest-bearing deposits	2,191	2,018	2,221	1,986
Interest checking	37	51	39	46
Savings products	561	441	535	448
Time deposits	2,476	224	3,327	212
Total deposits	5,265	2,734	6,122	2,692
Total U.S. Bancorp shareholders' equity	$ 17,552	$ 18,324	$ 17,360	$ 18,121