XML 121 R94.htm IDEA: XBRL DOCUMENT
v3.20.4

Debt (Unsecured Fixed Rate Debt Securities Issued Under Current Shelf Registration) (Details) - Unsecured Debt [Member] - USD ($) | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2020 | Apr. 07, 2020 | Jan. 31, 2020
2.150% Notes Due 2027 [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Issuance date | Jan. 31, 2020 |  |
Note amount |  |  | $ 500,000,000
Interest rate on note |  |  | 2.15%
Maturity date on new borrowing | Feb. 05, 2027 |  |
2.400% Notes Due 2030 [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Issuance date | Jan. 31, 2020 |  |
Note amount |  |  | $ 750,000,000
Interest rate on note |  |  | 2.40%
Maturity date on new borrowing | Feb. 05, 2030 |  |
3.250% Notes Due 2050 [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Issuance date | Jan. 31, 2020 |  |
Note amount |  |  | $ 1,000,000,000.0
Interest rate on note |  |  | 3.25%
Maturity date on new borrowing | Feb. 05, 2050 |  |
3.750% Notes Due 2070 [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Issuance date | Jan. 31, 2020 |  |
Note amount |  |  | $ 750,000,000
Interest rate on note |  |  | 3.75%
Maturity date on new borrowing | Feb. 05, 2070 |  |
3.250% Notes Due 2050 .[Member] |  |  |
Debt Instrument [Line Items] |  |  |
Issuance date | Apr. 07, 2020 |  |
Note amount |  | $ 750,000,000 |
Interest rate on note |  | 3.25% |
Maturity date on new borrowing | Feb. 05, 2050 |  |

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Date the debt instrument was issued, in CCYY-MM-DD format. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentIssuanceDate1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_DebtInstrumentMaturityDate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=unp_NotesDue20272150PercentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=unp_NotesDue20302400PercentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=unp_NotesDue20532500PercentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=unp_NotesDue20703750PercentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=unp_NotesDue20503250PercentApril2020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |