Basis of Presentation - Line of Business Financial Performance (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 3,197	$ 3,030
Net interest income (taxable-equivalent basis), Percent change	5.50%
Noninterest income	$ 2,267	2,230
Noninterest income, Percent change	1.70%
Securities gains (losses), net	$ 5	29
Securities gains (losses), net, Percent change	(82.80%)
Total net revenue	$ 5,469	5,289
Total net revenue, Percent change	3.40%
Noninterest expense, Percent change	5.30%
Other intangibles, Percent change	(11.40%)
Total noninterest expense, Percent change	5.00%
Income before provision and income taxes, Percent change	1.40%
Provision for credit losses, Percent change	(1.20%)
Income before income taxes, Percent change	1.90%
Income taxes and taxable-equivalent adjustment, Percent change	(28.80%)
Net income, Percent change	13.20%
Net (income) loss attributable to noncontrolling interests, Percent change	46.20%
Net income attributable to U.S. Bancorp, Percent change	13.70%
Noninterest expense	$ 3,016	2,865
Other intangibles	39	44
Total noninterest expense	3,055	2,909
Income before provision and income taxes	2,414	2,380
Provision for credit losses	341	345
Income before income taxes	2,073	2,035
Income taxes and taxable-equivalent adjustment	391	549
Net income	1,682	1,486
Net (income) loss attributable to noncontrolling interests	(7)	(13)
Net income attributable to U.S. Bancorp	1,675	1,473
Average Balance Sheet
Commercial	$ 97,465	93,739
Commercial, Percent change	4.00%
Commercial real estate	$ 40,366	43,158
Commercial real estate, Percent change	(6.50%)
Residential mortgages	$ 60,174	57,900
Residential mortgages, Percent change	3.90%
Credit card	$ 21,284	20,845
Credit card, Percent change	2.10%
Other retail	$ 57,051	53,784
Other retail, Percent change	6.10%
Total loans, excluding covered loans	$ 276,340	269,426
Total loans, excluding covered loans, Percent change	2.60%
Covered loans	$ 3,048	3,732
Covered loans, Percent change	(18.30%)
Total loans	$ 279,388	273,158
Total loans, Percent change	2.30%
Goodwill, Percent change	1.00%
Other intangible assets, Percent change	1.30%
Assets, Percent change	2.90%
Noninterest-bearing deposits, Percent change	(1.60%)
Interest checking, Percent change	7.10%
Savings products, Percent change	(2.40%)
Time deposits, Percent change	20.70%
Total deposits, Percent change	1.90%
Total U.S. Bancorp shareholders' equity, Percent change	1.90%
Goodwill	$ 9,440	9,347
Other intangible assets	3,349	3,307
Assets	454,288	441,311
Noninterest-bearing deposits	79,482	80,738
Interest checking	70,358	65,681
Savings products	147,755	151,368
Time deposits	36,985	30,646
Total deposits	334,580	328,433
Total U.S. Bancorp shareholders' equity	48,825	47,923
Corporate and Commercial Banking [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 724	712
Net interest income (taxable-equivalent basis), Percent change	1.70%
Noninterest income	$ 207	247
Noninterest income, Percent change	(16.20%)
Securities gains (losses), net		(3)
Total net revenue	$ 931	956
Total net revenue, Percent change	(2.60%)
Noninterest expense, Percent change	2.50%
Total noninterest expense, Percent change	2.50%
Income before provision and income taxes, Percent change	(6.20%)
Provision for credit losses, Percent change	(61.10%)
Income before income taxes, Percent change	(2.50%)
Income taxes and taxable-equivalent adjustment, Percent change	(33.00%)
Net income, Percent change	15.00%
Net income attributable to U.S. Bancorp, Percent change	15.00%
Noninterest expense	$ 404	394
Other intangibles	1	1
Total noninterest expense	405	395
Income before provision and income taxes	526	561
Provision for credit losses	14	36
Income before income taxes	512	525
Income taxes and taxable-equivalent adjustment	128	191
Net income	384	334
Net income attributable to U.S. Bancorp	384	334
Average Balance Sheet
Commercial	$ 74,808	72,414
Commercial, Percent change	3.30%
Commercial real estate	$ 19,137	21,305
Commercial real estate, Percent change	(10.20%)
Residential mortgages	$ 6	8
Residential mortgages, Percent change	(25.00%)
Total loans, excluding covered loans	$ 93,951	93,727
Total loans, excluding covered loans, Percent change	0.20%
Total loans	$ 93,951	93,727
Total loans, Percent change	0.20%
Other intangible assets, Percent change	(20.00%)
Assets, Percent change	0.30%
Noninterest-bearing deposits, Percent change	(6.90%)
Interest checking, Percent change	2.60%
Savings products, Percent change	(10.00%)
Time deposits, Percent change	32.40%
Total deposits, Percent change	(2.90%)
Total U.S. Bancorp shareholders' equity, Percent change	7.60%
Goodwill	$ 1,647	1,647
Other intangible assets	12	15
Assets	102,642	102,309
Noninterest-bearing deposits	34,388	36,939
Interest checking	9,493	9,256
Savings products	43,938	48,820
Time deposits	16,523	12,484
Total deposits	104,342	107,499
Total U.S. Bancorp shareholders' equity	10,417	9,680
Consumer and Business Banking [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 1,524	1,418
Net interest income (taxable-equivalent basis), Percent change	7.50%
Noninterest income	$ 568	571
Noninterest income, Percent change	(0.50%)
Total net revenue	$ 2,092	1,989
Total net revenue, Percent change	5.20%
Noninterest expense, Percent change	3.00%
Total noninterest expense, Percent change	3.00%
Income before provision and income taxes, Percent change	8.90%
Provision for credit losses, Percent change	(13.80%)
Income before income taxes, Percent change	11.10%
Income taxes and taxable-equivalent adjustment, Percent change	(23.60%)
Net income, Percent change	31.00%
Net income attributable to U.S. Bancorp, Percent change	31.00%
Noninterest expense	$ 1,291	1,253
Other intangibles	7	7
Total noninterest expense	1,298	1,260
Income before provision and income taxes	794	729
Provision for credit losses	56	65
Income before income taxes	738	664
Income taxes and taxable-equivalent adjustment	185	242
Net income	553	422
Net income attributable to U.S. Bancorp	553	422
Average Balance Sheet
Commercial	$ 9,838	9,913
Commercial, Percent change	(0.80%)
Commercial real estate	$ 18,217	18,551
Commercial real estate, Percent change	(1.80%)
Residential mortgages	$ 57,066	55,239
Residential mortgages, Percent change	3.30%
Other retail	$ 55,010	51,687
Other retail, Percent change	6.40%
Total loans, excluding covered loans	$ 140,131	135,390
Total loans, excluding covered loans, Percent change	3.50%
Covered loans	$ 3,048	3,717
Covered loans, Percent change	(18.00%)
Total loans	$ 143,179	139,107
Total loans, Percent change	2.90%
Other intangible assets, Percent change	3.70%
Assets, Percent change	2.50%
Noninterest-bearing deposits, Percent change	1.50%
Interest checking, Percent change	6.70%
Savings products, Percent change	2.80%
Time deposits, Percent change	(4.80%)
Total deposits, Percent change	3.10%
Total U.S. Bancorp shareholders' equity, Percent change	6.00%
Goodwill	$ 3,681	3,681
Other intangible assets	2,871	2,768
Assets	157,544	153,647
Noninterest-bearing deposits	27,381	26,965
Interest checking	49,400	46,298
Savings products	61,543	59,850
Time deposits	12,576	13,207
Total deposits	150,900	146,320
Total U.S. Bancorp shareholders' equity	12,219	11,522
Wealth Management and Investment Services [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 284	250
Net interest income (taxable-equivalent basis), Percent change	13.60%
Noninterest income	$ 432	399
Noninterest income, Percent change	8.30%
Total net revenue	$ 716	649
Total net revenue, Percent change	10.30%
Noninterest expense, Percent change	5.80%
Other intangibles, Percent change	(20.00%)
Total noninterest expense, Percent change	5.50%
Income before provision and income taxes, Percent change	18.30%
Income before income taxes, Percent change	18.40%
Income taxes and taxable-equivalent adjustment, Percent change	(18.00%)
Net income, Percent change	39.10%
Net income attributable to U.S. Bancorp, Percent change	39.10%
Noninterest expense	$ 421	398
Other intangibles	4	5
Total noninterest expense	425	403
Income before provision and income taxes	291	246
Provision for credit losses	1	1
Income before income taxes	290	245
Income taxes and taxable-equivalent adjustment	73	89
Net income	217	156
Net income attributable to U.S. Bancorp	217	156
Average Balance Sheet
Commercial	$ 3,660	3,190
Commercial, Percent change	14.70%
Commercial real estate	$ 509	514
Commercial real estate, Percent change	(1.00%)
Residential mortgages	$ 3,096	2,645
Residential mortgages, Percent change	17.10%
Other retail	$ 1,617	1,617
Total loans, excluding covered loans	$ 8,882	7,966
Total loans, excluding covered loans, Percent change	11.50%
Total loans	$ 8,882	7,966
Total loans, Percent change	11.50%
Goodwill, Percent change	0.30%
Other intangible assets, Percent change	(19.50%)
Assets, Percent change	3.70%
Noninterest-bearing deposits, Percent change	3.50%
Interest checking, Percent change	13.20%
Savings products, Percent change	(1.10%)
Time deposits, Percent change	(22.30%)
Total deposits, Percent change	0.40%
Total U.S. Bancorp shareholders' equity, Percent change	(0.20%)
Goodwill	$ 1,570	1,566
Other intangible assets	70	87
Assets	11,875	11,446
Noninterest-bearing deposits	14,329	13,841
Interest checking	11,423	10,087
Savings products	41,662	42,145
Time deposits	3,695	4,755
Total deposits	71,109	70,828
Total U.S. Bancorp shareholders' equity	2,399	2,403
Payment Services [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 612	595
Net interest income (taxable-equivalent basis), Percent change	2.90%
Noninterest income	$ 847	798
Noninterest income, Percent change	6.10%
Total net revenue	$ 1,459	1,393
Total net revenue, Percent change	4.70%
Noninterest expense, Percent change	8.70%
Other intangibles, Percent change	(12.90%)
Total noninterest expense, Percent change	7.70%
Income before provision and income taxes, Percent change	2.00%
Provision for credit losses, Percent change	12.90%
Income before income taxes, Percent change	(3.60%)
Income taxes and taxable-equivalent adjustment, Percent change	(33.50%)
Net income, Percent change	13.60%
Net income attributable to U.S. Bancorp, Percent change	16.30%
Noninterest expense	$ 702	646
Other intangibles	27	31
Total noninterest expense	729	677
Income before provision and income taxes	730	716
Provision for credit losses	272	241
Income before income taxes	458	475
Income taxes and taxable-equivalent adjustment	115	173
Net income	343	302
Net income attributable to U.S. Bancorp	343	295
Average Balance Sheet
Commercial	$ 8,354	7,611
Commercial, Percent change	9.80%
Credit card	$ 21,284	20,845
Credit card, Percent change	2.10%
Other retail	$ 424	480
Other retail, Percent change	(11.70%)
Total loans, excluding covered loans	$ 30,062	28,936
Total loans, excluding covered loans, Percent change	3.90%
Total loans	$ 30,062	28,936
Total loans, Percent change	3.90%
Goodwill, Percent change	3.60%
Other intangible assets, Percent change	(9.40%)
Assets, Percent change	4.60%
Noninterest-bearing deposits, Percent change	10.10%
Savings products, Percent change	4.00%
Total deposits, Percent change	9.70%
Total U.S. Bancorp shareholders' equity, Percent change	3.40%
Goodwill	$ 2,542	2,453
Other intangible assets	396	437
Assets	36,173	34,566
Noninterest-bearing deposits	1,127	1,024
Savings products	103	99
Time deposits	3	1
Total deposits	1,233	1,124
Total U.S. Bancorp shareholders' equity	6,622	6,405
Treasury and Corporate Support [Member]
Condensed Income Statement
Net interest income (taxable-equivalent basis)	$ 53	55
Net interest income (taxable-equivalent basis), Percent change	(3.60%)
Noninterest income	$ 213	215
Noninterest income, Percent change	(0.90%)
Securities gains (losses), net	$ 5	32
Securities gains (losses), net, Percent change	(84.40%)
Total net revenue	$ 271	302
Total net revenue, Percent change	(10.30%)
Noninterest expense, Percent change	13.80%
Total noninterest expense, Percent change	13.80%
Income before provision and income taxes, Percent change	(43.00%)
Income before income taxes, Percent change	(40.50%)
Income taxes and taxable-equivalent adjustment, Percent change	24.70%
Net income, Percent change	(32.00%)
Net (income) loss attributable to noncontrolling interests, Percent change	(16.70%)
Net income attributable to U.S. Bancorp, Percent change	(33.10%)
Noninterest expense	$ 198	174
Total noninterest expense	198	174
Income before provision and income taxes	73	128
Provision for credit losses	(2)	2
Income before income taxes	75	126
Income taxes and taxable-equivalent adjustment	(110)	(146)
Net income	185	272
Net (income) loss attributable to noncontrolling interests	(7)	(6)
Net income attributable to U.S. Bancorp	178	266
Average Balance Sheet
Commercial	$ 805	611
Commercial, Percent change	31.80%
Commercial real estate	$ 2,503	2,788
Commercial real estate, Percent change	(10.20%)
Residential mortgages	$ 6	8
Residential mortgages, Percent change	(25.00%)
Total loans, excluding covered loans	$ 3,314	3,407
Total loans, excluding covered loans, Percent change	(2.70%)
Covered loans		15
Total loans	$ 3,314	3,422
Total loans, Percent change	(3.20%)
Assets, Percent change	4.80%
Noninterest-bearing deposits, Percent change	14.60%
Interest checking, Percent change	5.00%
Savings products, Percent change	12.10%
Total U.S. Bancorp shareholders' equity, Percent change	(4.20%)
Assets	$ 146,054	139,343
Noninterest-bearing deposits	2,257	1,969
Interest checking	42	40
Savings products	509	454
Time deposits	4,188	199
Total deposits	6,996	2,662
Total U.S. Bancorp shareholders' equity	$ 17,168	$ 17,913