Pension and other post-retirement benefits - PBO/ABO/Fair value (Details 2) - CHF (SFr) SFr in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Switzerland \| Defined benefit pension plans
Defined benefit plan, Disclosure
PBO	SFr 15,432	SFr 15,885	SFr 15,885
ABO	14,534	14,841
Switzerland \| Defined benefit pension plans \| PBO exceeds fair value of plan assets
Defined benefit plan, Disclosure
PBO	0	0
ABO	0	0
Fair value of plan assets	0	0
Switzerland \| Defined benefit pension plans \| ABO exceeds fair value of plan assets
Defined benefit plan, Disclosure
PBO	0	0
ABO	0	0
Fair value of plan assets	0	0
International \| Defined benefit pension plans
Defined benefit plan, Disclosure
PBO	2,951	3,390	3,337
ABO	2,921	3,351
International \| Defined benefit pension plans \| PBO exceeds fair value of plan assets
Defined benefit plan, Disclosure
PBO	1,336	1,464
ABO	1,312	1,433
Fair value of plan assets	989	1,104
International \| Defined benefit pension plans \| ABO exceeds fair value of plan assets
Defined benefit plan, Disclosure
PBO	1,325	1,447
ABO	1,304	1,420
Fair value of plan assets	978	1,088
International \| Other post-retirement defined benefit plans
Defined benefit plan, Disclosure
PBO	160	173	184
ABO	160	173
Bank \| International \| Defined benefit pension plans
Defined benefit plan, Disclosure
PBO	2,951	3,390	3,337
ABO	2,921	3,351
Bank \| International \| Defined benefit pension plans \| PBO exceeds fair value of plan assets
Defined benefit plan, Disclosure
PBO	1,336	1,464
ABO	1,312	1,433
Fair value of plan assets	989	1,104
Bank \| International \| Defined benefit pension plans \| ABO exceeds fair value of plan assets
Defined benefit plan, Disclosure
PBO	1,325	1,447
ABO	1,304	1,420
Fair value of plan assets	978	1,088
Bank \| International \| Other post-retirement defined benefit plans
Defined benefit plan, Disclosure
PBO	160	173	SFr 184
ABO	SFr 160	SFr 173

Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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- Definition

Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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+ References

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- Definition

Fair value of plan assets for defined benefit pension plan with accumulated benefit obligation in excess of plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e2417-114920

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