Basis of Presentation - Line of Business Financial Performance (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 2,770	$ 2,744	$ 5,522	$ 5,450
Net interest income (taxable-equivalent basis), Percent change	0.90%		1.30%
Noninterest income	$ 2,272	2,444	$ 4,426	4,547
Noninterest income, Percent change	(7.00%)		(2.70%)
Securities gains (losses), net				5
Securities gains (losses), net, Percent change	0.00%		0.00%
Total net revenue	$ 5,042	5,188	$ 9,948	10,002
Total net revenue, Percent change	(2.80%)		(0.50%)
Noninterest expense, Percent change	(2.40%)		1.20%
Other intangibles, Percent change	(10.40%)		(11.30%)
Total noninterest expense, Percent change	(2.60%)		0.90%
Income before provision and income taxes, Percent change	(3.10%)		(2.20%)
Provision for credit losses, Percent change	(13.30%)		(13.50%)
Income before income taxes, Percent change	(1.50%)		(0.50%)
Income taxes and taxable-equivalent adjustment, Percent change	(3.30%)		(3.40%)
Net income, Percent change	(0.80%)		0.70%
Net (income) loss attributable to noncontrolling interests, Percent change			6.90%
Net income attributable to U.S. Bancorp, Percent change	(0.80%)		0.80%
Noninterest expense	$ 2,639	2,705	$ 5,261	5,200
Other intangibles	43	48	86	97
Total noninterest expense	2,682	2,753	5,347	5,297
Income before provision and income taxes	2,360	2,435	4,601	4,705
Provision for credit losses	281	324	545	630
Income before income taxes	2,079	2,111	4,056	4,075
Income taxes and taxable-equivalent adjustment	582	602	1,115	1,154
Net income	1,497	1,509	2,941	2,921
Net (income) loss attributable to noncontrolling interests	(14)	(14)	(27)	(29)
Net income attributable to U.S. Bancorp	1,483	1,495	2,914	2,892
Average Balance Sheet
Commercial	$ 83,253	75,020	$ 82,385	72,939
Commercial, Percent change	11.00%		13.00%
Commercial real estate	$ 42,446	40,497	$ 42,558	40,275
Commercial real estate, Percent change	4.80%		5.70%
Residential mortgages	$ 51,114	51,815	$ 51,269	51,700
Residential mortgages, Percent change	(1.40%)		(0.80%)
Credit card	$ 17,613	17,384	$ 17,718	17,395
Credit card, Percent change	1.30%		1.90%
Other retail	$ 47,069	47,928	$ 48,188	47,793
Other retail, Percent change	(1.80%)		0.80%
Total loans, excluding covered loans	$ 241,495	232,644	$ 242,118	230,102
Total loans, excluding covered loans, Percent change	3.80%		5.20%
Covered loans	$ 5,065	7,836	$ 5,133	8,080
Covered loans, Percent change	(35.40%)		(36.50%)
Total loans	$ 246,560	240,480	$ 247,251	238,182
Total loans, Percent change	2.50%		3.80%
Goodwill, Percent change	1.50%		1.70%
Other intangible assets, Percent change	(7.40%)		(9.00%)
Assets, Percent change	8.80%		9.60%
Noninterest-bearing deposits, Percent change	7.70%		6.50%
Interest checking, Percent change	4.20%		5.30%
Savings products, Percent change	22.70%		20.80%
Time deposits, Percent change	(14.10%)		(11.20%)
Total deposits, Percent change	8.90%		8.50%
Total U.S. Bancorp shareholders' equity, Percent change	4.50%		5.00%
Goodwill	$ 9,369	9,228	$ 9,373	9,216
Other intangible assets	3,117	3,365	3,097	3,403
Assets	407,901	374,769	404,885	369,569
Noninterest-bearing deposits	77,347	71,837	75,937	71,333
Interest checking	55,205	52,989	54,933	52,152
Savings products	116,969	95,361	113,465	93,910
Time deposits	36,223	42,164	37,787	42,533
Total deposits	285,744	262,351	282,122	259,928
Total U.S. Bancorp shareholders' equity	44,514	42,586	44,297	42,176
Wholesale Banking and Commercial Real Estate [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 505	507	$ 1,003	1,004
Net interest income (taxable-equivalent basis), Percent change	(0.40%)		(0.10%)
Noninterest income	$ 224	256	$ 444	498
Noninterest income, Percent change	(12.50%)		(10.80%)
Securities gains (losses), net, Percent change	0.00%		0.00%
Total net revenue	$ 729	763	$ 1,447	1,502
Total net revenue, Percent change	(4.50%)		(3.70%)
Noninterest expense, Percent change	2.80%		5.00%
Total noninterest expense, Percent change	2.80%		4.90%
Income before provision and income taxes, Percent change	(9.60%)		(9.80%)
Income before income taxes, Percent change	(10.00%)		(17.90%)
Income taxes and taxable-equivalent adjustment, Percent change	(10.30%)		(18.00%)
Net income, Percent change	(9.90%)		(17.90%)
Net income attributable to U.S. Bancorp, Percent change	(9.90%)		(17.90%)
Noninterest expense	$ 325	316	$ 656	625
Other intangibles	1	1	2	2
Total noninterest expense	326	317	658	627
Income before provision and income taxes	403	446	789	875
Provision for credit losses	18	18	75	5
Income before income taxes	385	428	714	870
Income taxes and taxable-equivalent adjustment	140	156	260	317
Net income	245	272	454	553
Net income attributable to U.S. Bancorp	245	272	454	553
Average Balance Sheet
Commercial	$ 63,326	57,378	$ 63,019	55,871
Commercial, Percent change	10.40%		12.80%
Commercial real estate	$ 19,407	18,313	$ 19,300	18,141
Commercial real estate, Percent change	6.00%		6.40%
Residential mortgages	$ 8	11	$ 8	12
Residential mortgages, Percent change	(27.30%)		(33.30%)
Other retail	$ 3	4	$ 3	4
Other retail, Percent change	(25.00%)		(25.00%)
Total loans, excluding covered loans	$ 82,744	75,706	$ 82,330	74,028
Total loans, excluding covered loans, Percent change	9.30%		11.20%
Covered loans		196		220
Total loans	$ 82,744	75,902	$ 82,330	74,248
Total loans, Percent change	9.00%		10.90%
Goodwill, Percent change	2.40%		2.50%
Assets, Percent change	10.10%		11.90%
Noninterest-bearing deposits, Percent change	14.00%		10.90%
Interest checking, Percent change	(34.10%)		(30.40%)
Savings products, Percent change	57.00%		54.50%
Time deposits, Percent change	(15.50%)		(11.10%)
Total deposits, Percent change	9.60%		9.50%
Total U.S. Bancorp shareholders' equity, Percent change	8.30%		8.90%
Goodwill	$ 1,647	1,609	$ 1,647	1,607
Other intangible assets	21	21	21	21
Assets	91,613	83,185	91,027	81,376
Noninterest-bearing deposits	35,226	30,904	34,814	31,393
Interest checking	7,472	11,336	7,571	10,878
Savings products	27,063	17,242	26,272	17,002
Time deposits	15,463	18,303	16,298	18,340
Total deposits	85,224	77,785	84,955	77,613
Total U.S. Bancorp shareholders' equity	8,114	7,489	8,081	7,418
Consumer and Small Business Banking [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 1,147	1,182	$ 2,292	2,382
Net interest income (taxable-equivalent basis), Percent change	(3.00%)		(3.80%)
Noninterest income	$ 631	680	$ 1,253	1,298
Noninterest income, Percent change	(7.20%)		(3.50%)
Securities gains (losses), net, Percent change	0.00%		0.00%
Total net revenue	$ 1,778	1,862	$ 3,545	3,680
Total net revenue, Percent change	(4.50%)		(3.70%)
Noninterest expense, Percent change	7.60%		6.90%
Other intangibles, Percent change	25.00%		25.00%
Total noninterest expense, Percent change	7.80%		7.00%
Income before provision and income taxes, Percent change	(23.60%)		(20.70%)
Provision for credit losses, Percent change	(56.70%)		(74.70%)
Income before income taxes, Percent change	(17.10%)		(9.00%)
Income taxes and taxable-equivalent adjustment, Percent change	(17.20%)		(9.20%)
Net income, Percent change	(17.10%)		(8.90%)
Net income attributable to U.S. Bancorp, Percent change	(17.10%)		(8.90%)
Noninterest expense	$ 1,212	1,126	$ 2,398	2,243
Other intangibles	10	8	20	16
Total noninterest expense	1,222	1,134	2,418	2,259
Income before provision and income taxes	556	728	1,127	1,421
Provision for credit losses	52	120	64	253
Income before income taxes	504	608	1,063	1,168
Income taxes and taxable-equivalent adjustment	183	221	386	425
Net income	321	387	677	743
Net income attributable to U.S. Bancorp	321	387	677	743
Average Balance Sheet
Commercial	$ 10,307	8,920	$ 9,979	8,628
Commercial, Percent change	15.50%		15.70%
Commercial real estate	$ 18,941	18,794	$ 19,070	18,709
Commercial real estate, Percent change	0.80%		1.90%
Residential mortgages	$ 49,337	50,480	$ 49,556	50,385
Residential mortgages, Percent change	(2.30%)		(1.60%)
Other retail	$ 44,955	45,800	$ 46,091	45,642
Other retail, Percent change	(1.80%)		1.00%
Total loans, excluding covered loans	$ 123,540	123,994	$ 124,696	123,364
Total loans, excluding covered loans, Percent change	(0.40%)		1.10%
Covered loans	$ 5,020	5,883	$ 5,091	5,966
Covered loans, Percent change	(14.70%)		(14.70%)
Total loans	$ 128,560	129,877	$ 129,787	129,330
Total loans, Percent change	(1.00%)		0.40%
Goodwill, Percent change	4.20%		4.50%
Other intangible assets, Percent change	(4.60%)		(6.90%)
Assets, Percent change	3.40%		3.40%
Noninterest-bearing deposits, Percent change	12.70%		12.90%
Interest checking, Percent change	12.20%		12.00%
Savings products, Percent change	9.20%		9.20%
Time deposits, Percent change	(9.60%)		(9.50%)
Total deposits, Percent change	8.00%		7.90%
Total U.S. Bancorp shareholders' equity, Percent change	(4.90%)		(2.60%)
Goodwill	$ 3,682	3,533	$ 3,682	3,523
Other intangible assets	2,564	2,689	2,529	2,715
Assets	147,492	142,661	147,018	142,175
Noninterest-bearing deposits	25,853	22,937	25,364	22,462
Interest checking	40,056	35,715	39,540	35,303
Savings products	53,640	49,125	53,089	48,605
Time deposits	16,020	17,722	16,484	18,213
Total deposits	135,569	125,499	134,477	124,583
Total U.S. Bancorp shareholders' equity	10,809	11,370	11,168	11,469
Wealth Management and Securities Services [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 91	96	$ 179	192
Net interest income (taxable-equivalent basis), Percent change	(5.20%)		(6.80%)
Noninterest income	$ 372	347	$ 728	686
Noninterest income, Percent change	7.20%		6.10%
Securities gains (losses), net, Percent change	0.00%		0.00%
Total net revenue	$ 463	443	$ 907	878
Total net revenue, Percent change	4.50%		3.30%
Noninterest expense, Percent change	4.80%		5.40%
Other intangibles, Percent change	(12.50%)		(17.60%)
Total noninterest expense, Percent change	4.40%		4.80%
Income before provision and income taxes, Percent change	4.90%		(2.00%)
Provision for credit losses, Percent change	(83.30%)
Income before income taxes, Percent change	10.30%		(0.50%)
Income taxes and taxable-equivalent adjustment, Percent change	11.40%
Net income, Percent change	9.70%		(0.80%)
Net income attributable to U.S. Bancorp, Percent change	9.70%		(0.80%)
Noninterest expense	$ 348	332	$ 701	665
Other intangibles	7	8	14	17
Total noninterest expense	355	340	715	682
Income before provision and income taxes	108	103	192	196
Provision for credit losses	1	6	(1)	2
Income before income taxes	107	97	193	194
Income taxes and taxable-equivalent adjustment	39	35	70	70
Net income	68	62	123	124
Net income attributable to U.S. Bancorp	68	62	123	124
Average Balance Sheet
Commercial	$ 2,256	1,922	$ 2,274	1,885
Commercial, Percent change	17.40%		20.60%
Commercial real estate	$ 558	605	$ 573	610
Commercial real estate, Percent change	(7.80%)		(6.10%)
Residential mortgages	$ 1,756	1,314	$ 1,692	1,293
Residential mortgages, Percent change	33.60%		30.90%
Other retail	$ 1,509	1,446	$ 1,480	1,460
Other retail, Percent change	4.40%		1.40%
Total loans, excluding covered loans	$ 6,079	5,287	$ 6,019	5,248
Total loans, excluding covered loans, Percent change	15.00%		14.70%
Covered loans	$ 1	6	$ 1	7
Covered loans, Percent change	(83.30%)		(85.70%)
Total loans	$ 6,080	5,293	$ 6,020	5,255
Total loans, Percent change	14.90%		14.60%
Goodwill, Percent change	0.10%		0.10%
Other intangible assets, Percent change	(21.30%)		(20.40%)
Assets, Percent change	7.80%		9.70%
Noninterest-bearing deposits, Percent change	(12.20%)		(12.80%)
Interest checking, Percent change	32.00%		33.80%
Savings products, Percent change	25.30%		20.60%
Time deposits, Percent change	(17.40%)		(22.70%)
Total deposits, Percent change	11.70%		8.80%
Total U.S. Bancorp shareholders' equity, Percent change	0.80%		0.50%
Goodwill	$ 1,567	1,566	$ 1,567	1,566
Other intangible assets	129	164	133	167
Assets	8,987	8,338	9,091	8,286
Noninterest-bearing deposits	13,776	15,687	13,256	15,208
Interest checking	7,043	5,336	7,196	5,380
Savings products	35,698	28,487	33,537	27,800
Time deposits	3,498	4,236	3,248	4,200
Total deposits	60,015	53,746	57,237	52,588
Total U.S. Bancorp shareholders' equity	2,304	2,286	2,302	2,291
Payment Services [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 459	418	$ 926	834
Net interest income (taxable-equivalent basis), Percent change	9.80%		11.00%
Noninterest income	$ 850	832	$ 1,627	1,607
Noninterest income, Percent change	2.20%		1.20%
Securities gains (losses), net, Percent change	0.00%		0.00%
Total net revenue	$ 1,309	1,250	$ 2,553	2,441
Total net revenue, Percent change	4.70%		4.60%
Noninterest expense, Percent change	15.10%		9.50%
Other intangibles, Percent change	(19.40%)		(19.40%)
Total noninterest expense, Percent change	13.30%		8.00%
Income before provision and income taxes, Percent change	(3.20%)		1.30%
Provision for credit losses, Percent change	14.30%		5.70%
Income before income taxes, Percent change	(10.10%)		(0.70%)
Income taxes and taxable-equivalent adjustment, Percent change	(10.60%)		(1.30%)
Net income, Percent change	(9.80%)		(0.40%)
Net (income) loss attributable to noncontrolling interests, Percent change	11.10%		11.10%
Net income attributable to U.S. Bancorp, Percent change	(9.80%)
Noninterest expense	$ 657	571	$ 1,249	1,141
Other intangibles	25	31	50	62
Total noninterest expense	682	602	1,299	1,203
Income before provision and income taxes	627	648	1,254	1,238
Provision for credit losses	208	182	405	383
Income before income taxes	419	466	849	855
Income taxes and taxable-equivalent adjustment	152	170	308	312
Net income	267	296	541	543
Net (income) loss attributable to noncontrolling interests	(8)	(9)	(16)	(18)
Net income attributable to U.S. Bancorp	259	287	525	525
Average Balance Sheet
Commercial	$ 7,083	6,522	$ 6,840	6,261
Commercial, Percent change	8.60%		9.20%
Credit card	$ 17,613	17,384	$ 17,718	17,395
Credit card, Percent change	1.30%		1.90%
Other retail	$ 602	678	$ 614	687
Other retail, Percent change	(11.20%)		(10.60%)
Total loans, excluding covered loans	$ 25,298	24,584	$ 25,172	24,343
Total loans, excluding covered loans, Percent change	2.90%		3.40%
Covered loans		5		5
Total loans	$ 25,298	24,589	$ 25,172	24,348
Total loans, Percent change	2.90%		3.40%
Goodwill, Percent change	(1.90%)		(1.70%)
Other intangible assets, Percent change	(17.90%)		(17.20%)
Assets, Percent change	1.90%		2.00%
Noninterest-bearing deposits, Percent change	23.90%		25.70%
Interest checking, Percent change	6.90%		7.80%
Savings products, Percent change	18.40%		21.90%
Total deposits, Percent change	16.50%		18.00%
Total U.S. Bancorp shareholders' equity, Percent change	2.70%		2.30%
Goodwill	$ 2,473	2,520	$ 2,477	2,520
Other intangible assets	403	491	414	500
Assets	31,510	30,914	31,251	30,642
Noninterest-bearing deposits	881	711	886	705
Interest checking	602	563	595	552
Savings products	90	76	89	73
Total deposits	1,573	1,350	1,570	1,330
Total U.S. Bancorp shareholders' equity	5,817	5,665	5,799	5,666
Treasury and Corporate Support [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 568	541	$ 1,122	1,038
Net interest income (taxable-equivalent basis), Percent change	5.00%		8.10%
Noninterest income	$ 195	329	$ 374	458
Noninterest income, Percent change	(40.70%)		(18.30%)
Securities gains (losses), net				5
Securities gains (losses), net, Percent change	0.00%		0.00%
Total net revenue	$ 763	870	$ 1,496	1,501
Total net revenue, Percent change	(12.30%)		(0.30%)
Noninterest expense, Percent change	(73.10%)		(51.10%)
Total noninterest expense, Percent change	(73.10%)		(51.10%)
Income before provision and income taxes, Percent change	30.60%		27.10%
Income before income taxes, Percent change	29.70%		25.20%
Net income, Percent change	21.10%		19.60%
Net (income) loss attributable to noncontrolling interests, Percent change	(20.00%)
Net income attributable to U.S. Bancorp, Percent change	21.10%		19.90%
Noninterest expense	$ 97	360	$ 257	526
Total noninterest expense	97	360	257	526
Income before provision and income taxes	666	510	1,239	975
Provision for credit losses	2	(2)	2	(13)
Income before income taxes	664	512	1,237	988
Income taxes and taxable-equivalent adjustment	68	20	91	30
Net income	596	492	1,146	958
Net (income) loss attributable to noncontrolling interests	(6)	(5)	(11)	(11)
Net income attributable to U.S. Bancorp	590	487	1,135	947
Average Balance Sheet
Commercial	$ 281	278	$ 273	294
Commercial, Percent change	1.10%		(7.10%)
Commercial real estate	$ 3,540	2,785	$ 3,615	2,815
Commercial real estate, Percent change	27.10%		28.40%
Residential mortgages	$ 13	10	$ 13	10
Residential mortgages, Percent change	30.00%		30.00%
Total loans, excluding covered loans	$ 3,834	3,073	$ 3,901	3,119
Total loans, excluding covered loans, Percent change	24.80%		25.10%
Covered loans	$ 44	1,746	$ 41	1,882
Covered loans, Percent change	(97.50%)		(97.80%)
Total loans	$ 3,878	4,819	$ 3,942	5,001
Total loans, Percent change	(19.50%)		(21.20%)
Assets, Percent change	17.00%		18.10%
Noninterest-bearing deposits, Percent change	0.80%		3.30%
Interest checking, Percent change	(17.90%)		(20.50%)
Savings products, Percent change	10.90%		11.20%
Time deposits, Percent change	(34.70%)		(1.30%)
Total deposits, Percent change	(15.30%)		1.80%
Total U.S. Bancorp shareholders' equity, Percent change	10.70%		10.50%
Assets	$ 128,299	109,671	$ 126,498	107,090
Noninterest-bearing deposits	1,611	1,598	1,617	1,565
Interest checking	32	39	31	39
Savings products	478	431	478	430
Time deposits	1,242	1,903	1,757	1,780
Total deposits	3,363	3,971	3,883	3,814
Total U.S. Bancorp shareholders' equity	$ 17,470	$ 15,776	$ 16,947	$ 15,332