Basis of Presentation - Line of Business Financial Performance (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 3,186	$ 2,943	$ 9,249	$ 8,727
Net interest income (taxable-equivalent basis), Percent change	8.30%		6.00%
Noninterest income	$ 2,413	2,435	$ 7,123	7,130
Noninterest income, Percent change	(0.90%)		(0.10%)
Securities gains (losses), net	$ 9	10	$ 47	16
Securities gains (losses), net, Percent change	(10.00%)
Total net revenue	$ 5,608	5,388	$ 16,419	15,873
Total net revenue, Percent change	4.10%		3.40%
Noninterest expense, Percent change	3.80%		3.90%
Other intangibles, Percent change	(2.20%)		(2.20%)
Total noninterest expense, Percent change	3.70%		3.90%
Income before provision and income taxes, Percent change	4.60%		2.90%
Provision for credit losses, Percent change	10.80%		7.40%
Income before income taxes, Percent change	3.60%		2.20%
Income taxes and taxable-equivalent adjustment, Percent change	3.90%		1.40%
Net income, Percent change	3.50%		2.60%
Net (income) loss attributable to noncontrolling interests, Percent change	57.10%		27.90%
Net income attributable to U.S. Bancorp, Percent change	4.10%		2.90%
Noninterest expense	$ 2,995	2,886	$ 8,875	8,538
Other intangibles	44	45	131	134
Total noninterest expense	3,039	2,931	9,006	8,672
Income before provision and income taxes	2,569	2,457	7,413	7,201
Provision for credit losses	360	325	1,055	982
Income before income taxes	2,209	2,132	6,358	6,219
Income taxes and taxable-equivalent adjustment	640	616	1,791	1,766
Net income	1,569	1,516	4,567	4,453
Net (income) loss attributable to noncontrolling interests	(6)	(14)	(31)	(43)
Net income attributable to U.S. Bancorp	1,563	1,502	4,536	4,410
Average Balance Sheet
Commercial	$ 96,633	92,369	$ 95,347	91,451
Commercial, Percent change	4.60%		4.30%
Commercial real estate	$ 41,621	43,374	$ 42,437	42,922
Commercial real estate, Percent change	(4.00%)		(1.10%)
Residential mortgages	$ 59,030	56,284	$ 58,496	55,334
Residential mortgages, Percent change	4.90%		5.70%
Credit card	$ 20,926	20,628	$ 20,801	20,339
Credit card, Percent change	1.40%		2.30%
Other retail	$ 56,069	52,851	$ 54,835	51,809
Other retail, Percent change	6.10%		5.80%
Total loans, excluding covered loans	$ 274,279	265,506	$ 271,916	261,855
Total loans, excluding covered loans, Percent change	3.30%		3.80%
Covered loans	$ 3,347	4,131	$ 3,538	4,324
Covered loans, Percent change	(19.00%)		(18.20%)
Total loans	$ 277,626	269,637	$ 275,454	266,179
Total loans, Percent change	3.00%		3.50%
Goodwill, Percent change	0.10%		(0.10%)
Other intangible assets, Percent change	10.40%		7.40%
Assets, Percent change	2.90%		3.90%
Noninterest-bearing deposits, Percent change	(0.10%)		2.40%
Interest checking, Percent change	7.30%		10.30%
Savings products, Percent change	5.80%		12.70%
Time deposits, Percent change	12.20%		(2.40%)
Total deposits, Percent change	5.20%		7.90%
Total U.S. Bancorp shareholders' equity, Percent change	2.20%		2.30%
Goodwill	$ 9,365	9,358	$ 9,355	9,361
Other intangible assets	3,178	2,879	3,239	3,017
Assets	450,630	437,863	446,049	429,421
Noninterest-bearing deposits	81,964	82,021	81,808	79,928
Interest checking	68,066	63,456	67,021	60,746
Savings products	148,721	140,616	150,121	133,191
Time deposits	36,400	32,455	32,660	33,447
Total deposits	335,151	318,548	331,610	307,312
Total U.S. Bancorp shareholders' equity	48,819	47,791	48,342	47,240
Wholesale Banking and Commercial Real Estate [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 616	563	$ 1,806	1,638
Net interest income (taxable-equivalent basis), Percent change	9.40%		10.30%
Noninterest income	$ 215	220	$ 697	676
Noninterest income, Percent change	(2.30%)		3.10%
Securities gains (losses), net			$ (3)
Total net revenue	$ 831	783	$ 2,500	2,314
Total net revenue, Percent change	6.10%		8.00%
Noninterest expense, Percent change	11.50%		11.40%
Total noninterest expense, Percent change	11.50%		11.40%
Income before provision and income taxes, Percent change	1.60%		5.10%
Provision for credit losses, Percent change			(97.40%)
Income before income taxes, Percent change	25.10%		44.00%
Income taxes and taxable-equivalent adjustment, Percent change	24.80%		43.80%
Net income, Percent change	25.30%		44.10%
Net income attributable to U.S. Bancorp, Percent change	25.30%		44.10%
Noninterest expense	$ 396	355	$ 1,188	1,066
Other intangibles	1	1	3	3
Total noninterest expense	397	356	1,191	1,069
Income before provision and income taxes	434	427	1,309	1,245
Provision for credit losses	(9)	73	9	342
Income before income taxes	443	354	1,300	903
Income taxes and taxable-equivalent adjustment	161	129	473	329
Net income	282	225	827	574
Net income attributable to U.S. Bancorp	282	225	827	574
Average Balance Sheet
Commercial	$ 73,882	70,814	$ 73,236	70,414
Commercial, Percent change	4.30%		4.00%
Commercial real estate	$ 20,115	21,466	$ 20,742	21,089
Commercial real estate, Percent change	(6.30%)		(1.60%)
Residential mortgages	$ 6	8	$ 7	7
Residential mortgages, Percent change	(25.00%)
Other retail		2	$ 1	2
Other retail, Percent change			(50.00%)
Total loans, excluding covered loans	$ 94,003	92,290	$ 93,986	91,512
Total loans, excluding covered loans, Percent change	1.90%		2.70%
Total loans	$ 94,003	92,290	$ 93,986	91,512
Total loans, Percent change	1.90%		2.70%
Other intangible assets, Percent change	(18.80%)		(17.60%)
Assets, Percent change	1.50%		2.60%
Noninterest-bearing deposits, Percent change	(3.60%)		(0.90%)
Interest checking, Percent change	0.80%		15.90%
Savings products, Percent change	1.90%		16.30%
Time deposits, Percent change	45.40%		17.20%
Total deposits, Percent change	5.50%		10.00%
Total U.S. Bancorp shareholders' equity, Percent change	10.60%		10.40%
Goodwill	$ 1,647	1,647	$ 1,647	1,647
Other intangible assets	13	16	14	17
Assets	102,327	100,864	102,580	99,932
Noninterest-bearing deposits	35,353	36,685	36,217	36,543
Interest checking	9,710	9,629	9,505	8,202
Savings products	45,143	44,301	46,563	40,043
Time deposits	19,611	13,489	15,238	12,999
Total deposits	109,817	104,104	107,523	97,787
Total U.S. Bancorp shareholders' equity	9,952	8,997	9,852	8,927
Consumer and Small Business Banking [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 1,309	1,199	$ 3,789	3,523
Net interest income (taxable-equivalent basis), Percent change	9.20%		7.60%
Noninterest income	$ 632	712	$ 1,837	1,899
Noninterest income, Percent change	(11.20%)		(3.30%)
Total net revenue	$ 1,941	1,911	$ 5,626	5,422
Total net revenue, Percent change	1.60%		3.80%
Noninterest expense, Percent change	(2.10%)		2.00%
Other intangibles, Percent change			(8.30%)
Total noninterest expense, Percent change	(2.10%)		1.90%
Income before provision and income taxes, Percent change	9.30%		7.90%
Income before income taxes, Percent change	0.90%		(6.10%)
Income taxes and taxable-equivalent adjustment, Percent change	0.50%		(6.20%)
Net income, Percent change	1.10%		(6.00%)
Net income attributable to U.S. Bancorp, Percent change	1.10%		(6.00%)
Noninterest expense	$ 1,266	1,293	$ 3,821	3,746
Other intangibles	8	8	22	24
Total noninterest expense	1,274	1,301	3,843	3,770
Income before provision and income taxes	667	610	1,783	1,652
Provision for credit losses	97	45	252	22
Income before income taxes	570	565	1,531	1,630
Income taxes and taxable-equivalent adjustment	207	206	557	594
Net income	363	359	974	1,036
Net income attributable to U.S. Bancorp	363	359	974	1,036
Average Balance Sheet
Commercial	$ 10,317	10,546	$ 10,157	10,367
Commercial, Percent change	(2.20%)		(2.00%)
Commercial real estate	$ 18,353	18,307	$ 18,469	18,150
Commercial real estate, Percent change	0.30%		1.80%
Residential mortgages	$ 56,131	53,933	$ 55,725	53,127
Residential mortgages, Percent change	4.10%		4.90%
Other retail	$ 53,932	50,786	$ 52,710	49,738
Other retail, Percent change	6.20%		6.00%
Total loans, excluding covered loans	$ 138,733	133,572	$ 137,061	131,382
Total loans, excluding covered loans, Percent change	3.90%		4.30%
Covered loans	$ 3,347	4,107	$ 3,531	4,289
Covered loans, Percent change	(18.50%)		(17.70%)
Total loans	$ 142,080	137,679	$ 140,592	135,671
Total loans, Percent change	3.20%		3.60%
Other intangible assets, Percent change	19.00%		14.20%
Assets, Percent change	2.10%		2.80%
Noninterest-bearing deposits, Percent change	1.20%		2.10%
Interest checking, Percent change	8.10%		8.90%
Savings products, Percent change	5.30%		6.00%
Time deposits, Percent change	(9.70%)		(9.90%)
Total deposits, Percent change	3.90%		4.50%
Total U.S. Bancorp shareholders' equity, Percent change	1.60%		3.10%
Goodwill	$ 3,681	3,681	$ 3,682	3,681
Other intangible assets	2,701	2,270	2,733	2,394
Assets	156,737	153,501	154,894	150,711
Noninterest-bearing deposits	28,705	28,355	27,666	27,092
Interest checking	47,401	43,834	47,035	43,184
Savings products	60,821	57,759	60,452	57,035
Time deposits	12,899	14,282	12,975	14,394
Total deposits	149,826	144,230	148,128	141,705
Total U.S. Bancorp shareholders' equity	11,489	11,312	11,482	11,138
Wealth Management and Securities Services [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 192	135	$ 558	374
Net interest income (taxable-equivalent basis), Percent change	42.20%		49.20%
Noninterest income	$ 411	403	$ 1,222	1,183
Noninterest income, Percent change	2.00%		3.30%
Total net revenue	$ 603	538	$ 1,780	1,557
Total net revenue, Percent change	12.10%		14.30%
Noninterest expense, Percent change	4.40%		7.30%
Other intangibles, Percent change	(16.70%)		(16.70%)
Total noninterest expense, Percent change	4.10%		6.90%
Income before provision and income taxes, Percent change	33.10%		34.00%
Income before income taxes, Percent change	31.50%		33.20%
Income taxes and taxable-equivalent adjustment, Percent change	31.50%		33.50%
Net income, Percent change	31.60%		33.00%
Net income attributable to U.S. Bancorp, Percent change	31.60%		33.00%
Noninterest expense	$ 401	384	$ 1,194	1,113
Other intangibles	5	6	15	18
Total noninterest expense	406	390	1,209	1,131
Income before provision and income taxes	197	148	571	426
Provision for credit losses	1	(1)	1	(2)
Income before income taxes	196	149	570	428
Income taxes and taxable-equivalent adjustment	71	54	207	155
Net income	125	95	363	273
Net income attributable to U.S. Bancorp	125	95	363	273
Average Balance Sheet
Commercial	$ 3,504	2,892	$ 3,356	2,874
Commercial, Percent change	21.20%		16.80%
Commercial real estate	$ 514	516	$ 511	524
Commercial real estate, Percent change	(0.40%)		(2.50%)
Residential mortgages	$ 2,893	2,343	$ 2,764	2,200
Residential mortgages, Percent change	23.50%		25.60%
Other retail	$ 1,684	1,548	$ 1,658	1,537
Other retail, Percent change	8.80%		7.90%
Total loans, excluding covered loans	$ 8,595	7,299	$ 8,289	7,135
Total loans, excluding covered loans, Percent change	17.80%		16.20%
Total loans	$ 8,595	7,299	$ 8,289	7,135
Total loans, Percent change	17.80%		16.20%
Goodwill, Percent change	0.10%
Other intangible assets, Percent change	(20.20%)		(20.20%)
Assets, Percent change	10.70%		11.70%
Noninterest-bearing deposits, Percent change	6.60%		12.00%
Interest checking, Percent change	9.60%		12.00%
Savings products, Percent change	11.20%		19.80%
Time deposits, Percent change	(6.80%)		11.80%
Total deposits, Percent change	8.90%		16.50%
Total U.S. Bancorp shareholders' equity, Percent change	0.10%		0.20%
Goodwill	$ 1,568	1,567	$ 1,567	1,567
Other intangible assets	79	99	83	104
Assets	11,495	10,383	11,454	10,251
Noninterest-bearing deposits	14,715	13,803	14,836	13,249
Interest checking	10,917	9,958	10,438	9,319
Savings products	42,209	37,966	42,559	35,520
Time deposits	3,521	3,776	4,182	3,742
Total deposits	71,362	65,503	72,015	61,830
Total U.S. Bancorp shareholders' equity	2,381	2,378	2,383	2,379
Payment Services [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 563	538	$ 1,653	1,579
Net interest income (taxable-equivalent basis), Percent change	4.60%		4.70%
Noninterest income	$ 920	912	$ 2,686	2,651
Noninterest income, Percent change	0.90%		1.30%
Total net revenue	$ 1,483	1,450	$ 4,339	4,230
Total net revenue, Percent change	2.30%		2.60%
Noninterest expense, Percent change	6.80%		6.60%
Other intangibles, Percent change			2.20%
Total noninterest expense, Percent change	6.50%		6.40%
Income before provision and income taxes, Percent change	(1.60%)		(1.00%)
Provision for credit losses, Percent change	29.80%		29.10%
Income before income taxes, Percent change	(13.50%)		(12.60%)
Income taxes and taxable-equivalent adjustment, Percent change	(13.50%)		(12.70%)
Net income, Percent change	(13.40%)		(12.60%)
Net (income) loss attributable to noncontrolling interests, Percent change			48.00%
Net income attributable to U.S. Bancorp, Percent change	(11.40%)		(11.70%)
Noninterest expense	$ 707	662	$ 2,069	1,941
Other intangibles	30	30	91	89
Total noninterest expense	737	692	2,160	2,030
Income before provision and income taxes	746	758	2,179	2,200
Provision for credit losses	270	208	794	615
Income before income taxes	476	550	1,385	1,585
Income taxes and taxable-equivalent adjustment	173	200	504	577
Net income	303	350	881	1,008
Net (income) loss attributable to noncontrolling interests		(8)	(13)	(25)
Net income attributable to U.S. Bancorp	303	342	868	983
Average Balance Sheet
Commercial	$ 8,233	7,766	$ 7,942	7,438
Commercial, Percent change	6.00%		6.80%
Credit card	$ 20,926	20,628	$ 20,801	20,339
Credit card, Percent change	1.40%		2.30%
Other retail	$ 453	515	$ 466	532
Other retail, Percent change	(12.00%)		(12.40%)
Total loans, excluding covered loans	$ 29,612	28,909	$ 29,209	28,309
Total loans, excluding covered loans, Percent change	2.40%		3.20%
Total loans	$ 29,612	28,909	$ 29,209	28,309
Total loans, Percent change	2.40%		3.20%
Goodwill, Percent change	0.20%		(0.30%)
Other intangible assets, Percent change	(22.10%)		(18.50%)
Assets, Percent change	0.90%		1.70%
Noninterest-bearing deposits, Percent change	7.90%		8.00%
Savings products, Percent change	5.10%		4.10%
Total deposits, Percent change	7.60%		7.70%
Total U.S. Bancorp shareholders' equity, Percent change	(2.80%)		(1.30%)
Goodwill	$ 2,469	2,463	$ 2,459	2,466
Other intangible assets	385	494	409	502
Assets	35,035	34,715	34,794	34,226
Noninterest-bearing deposits	1,029	954	1,023	947
Savings products	103	98	101	97
Total deposits	1,132	1,052	1,124	1,044
Total U.S. Bancorp shareholders' equity	6,206	6,385	6,280	6,361
Treasury and Corporate Support [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 506	508	$ 1,443	1,613
Net interest income (taxable-equivalent basis), Percent change	(0.40%)		(10.50%)
Noninterest income	$ 235	188	$ 681	721
Noninterest income, Percent change	25.00%		(5.50%)
Securities gains (losses), net	$ 9	10	$ 50	16
Securities gains (losses), net, Percent change	(10.00%)
Total net revenue	$ 750	706	$ 2,174	2,350
Total net revenue, Percent change	6.20%		(7.50%)
Noninterest expense, Percent change	17.20%		(10.30%)
Total noninterest expense, Percent change	17.20%		(10.30%)
Income before provision and income taxes, Percent change	2.10%		(6.40%)
Income before income taxes, Percent change	1.90%		(6.00%)
Income taxes and taxable-equivalent adjustment, Percent change	3.70%		(55.00%)
Net income, Percent change	1.80%		(2.60%)
Net income attributable to U.S. Bancorp, Percent change	1.90%		(2.60%)
Noninterest expense	$ 225	192	$ 603	672
Total noninterest expense	225	192	603	672
Income before provision and income taxes	525	514	1,571	1,678
Provision for credit losses	1		(1)	5
Income before income taxes	524	514	1,572	1,673
Income taxes and taxable-equivalent adjustment	28	27	50	111
Net income	496	487	1,522	1,562
Net (income) loss attributable to noncontrolling interests	(6)	(6)	(18)	(18)
Net income attributable to U.S. Bancorp	490	481	1,504	1,544
Average Balance Sheet
Commercial	$ 697	351	$ 656	358
Commercial, Percent change	98.60%		83.20%
Commercial real estate	$ 2,639	3,085	$ 2,715	3,159
Commercial real estate, Percent change	(14.50%)		(14.10%)
Total loans, excluding covered loans	$ 3,336	3,436	$ 3,371	3,517
Total loans, excluding covered loans, Percent change	(2.90%)		(4.20%)
Covered loans		24	$ 7	35
Covered loans, Percent change			(80.00%)
Total loans	$ 3,336	3,460	$ 3,378	3,552
Total loans, Percent change	(3.60%)		(4.90%)
Assets, Percent change	4.80%		6.00%
Noninterest-bearing deposits, Percent change	(2.80%)		(1.50%)
Interest checking, Percent change	8.60%		4.90%
Savings products, Percent change	(9.60%)		(10.10%)
Time deposits, Percent change	(59.40%)		(88.50%)
Total deposits, Percent change	(17.60%)		(43.00%)
Total U.S. Bancorp shareholders' equity, Percent change	0.40%		(0.50%)
Assets	$ 145,036	138,400	$ 142,327	134,301
Noninterest-bearing deposits	2,162	2,224	2,066	2,097
Interest checking	38	35	43	41
Savings products	445	492	446	496
Time deposits	369	908	265	2,312
Total deposits	3,014	3,659	2,820	4,946
Total U.S. Bancorp shareholders' equity	$ 18,791	$ 18,719	$ 18,345	$ 18,435