Employee Benefit Plans - Benefit Obligations Weighted Average Assumptions (Details)	Jan. 31, 2019	Jan. 31, 2018
Qualified
Defined Benefit Plan Disclosure [Line Items]
Discount rate (percentage)	4.25%	4.00%
Rate of increase in compensation (percentage)	3.00%	3.00%
Excess/SRIP
Defined Benefit Plan Disclosure [Line Items]
Discount rate (percentage)	4.25%	3.75%
Rate of increase in compensation (percentage)	6.50%	6.50%
Other
Defined Benefit Plan Disclosure [Line Items]
Discount rate (percentage)	0.81%	0.83%
Rate of increase in compensation (percentage)	2.56%	1.13%
Excess Plan
Defined Benefit Plan Disclosure [Line Items]
Rate of increase in compensation (percentage)	4.25%	4.25%
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate (percentage)	4.50%	4.00%

Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(1)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

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- Definition

Weighted average rate increase of compensation, used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(2)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

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- 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.

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