XML 46 R81.htm IDEA: XBRL DOCUMENT v2.4.1.9
RETIREMENT BENEFITS - Net (Benefit) Expense (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Defined Benefit Plan Disclosure      
Percentage of the significant plans over global pension and postretirement liabilities, which utilize quarterly measurement policy 80.00%c_DefinedBenefitPlanSignificantPlansPercentageCapturedOverTotalPensionAndPostretirementLiabilitiesUtilizingQuarterlyMeasurement    
U.S. Pension Plans      
Amortization of unrecognized      
Total net (benefit) expense $ (184)us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember
$ (173)us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember
$ (183)us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember
U.S. Pension Plans | Effect of change in the measurement policy from annually to quarterly      
Amortization of unrecognized      
Total net (benefit) expense 0us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_DefinedBenefitPlansChangeInMeasurementAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember
(23)us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_DefinedBenefitPlansChangeInMeasurementAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember
0us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_DefinedBenefitPlansChangeInMeasurementAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember
U.S. Qualified Pension Plan      
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]      
Benefits earned during the year 6us-gaap_DefinedBenefitPlanServiceCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
8us-gaap_DefinedBenefitPlanServiceCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
12us-gaap_DefinedBenefitPlanServiceCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
Interest cost on benefit obligation 541us-gaap_DefinedBenefitPlanInterestCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
538us-gaap_DefinedBenefitPlanInterestCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
565us-gaap_DefinedBenefitPlanInterestCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
Expected return on plan assets (878)us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
(863)us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
(897)us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
Amortization of unrecognized      
Prior service (benefit) cost (3)us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
(4)us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
(1)us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
Net actuarial loss 105us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
104us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
96us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
Curtailment loss 0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToCurtailments
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
21us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToCurtailments
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToCurtailments
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
Settlement (gain) loss 0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
Special termination benefits 0us-gaap_DefinedBenefitPlanOtherCosts
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
0us-gaap_DefinedBenefitPlanOtherCosts
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
0us-gaap_DefinedBenefitPlanOtherCosts
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
U.S. Qualified Pension Plan | Before adjustment due to change in accounting policy      
Amortization of unrecognized      
Total net (benefit) expense (229)us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_BeforeAdjustmentDueToChangeInAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
(196)us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_BeforeAdjustmentDueToChangeInAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
(225)us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_BeforeAdjustmentDueToChangeInAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesQualifiedPensionPlansMember
U.S. Nonqualified Pension Plan | Before adjustment due to change in accounting policy      
Amortization of unrecognized      
Total net (benefit) expense 45us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_BeforeAdjustmentDueToChangeInAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesNonqualifiedPensionPlansMember
46us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_BeforeAdjustmentDueToChangeInAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesNonqualifiedPensionPlansMember
42us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_BeforeAdjustmentDueToChangeInAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= c_UnitedStatesNonqualifiedPensionPlansMember
Non - U.S. Pension Plans      
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]      
Benefits earned during the year 178us-gaap_DefinedBenefitPlanServiceCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
210us-gaap_DefinedBenefitPlanServiceCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
199us-gaap_DefinedBenefitPlanServiceCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
Interest cost on benefit obligation 376us-gaap_DefinedBenefitPlanInterestCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
384us-gaap_DefinedBenefitPlanInterestCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
367us-gaap_DefinedBenefitPlanInterestCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
Expected return on plan assets (384)us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
(396)us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
(399)us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
Amortization of unrecognized      
Prior service (benefit) cost 1us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
4us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
4us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
Net actuarial loss 77us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
95us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
77us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
Curtailment loss 14us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToCurtailments
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
4us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToCurtailments
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
10us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToCurtailments
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
Settlement (gain) loss 53us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
13us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
35us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
Special termination benefits 9us-gaap_DefinedBenefitPlanOtherCosts
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
8us-gaap_DefinedBenefitPlanOtherCosts
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
1us-gaap_DefinedBenefitPlanOtherCosts
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
Total net (benefit) expense 324us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
322us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
294us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
Non - U.S. Pension Plans | Before adjustment due to change in accounting policy      
Amortization of unrecognized      
Total net (benefit) expense 324us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_BeforeAdjustmentDueToChangeInAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
322us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_BeforeAdjustmentDueToChangeInAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
294us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_BeforeAdjustmentDueToChangeInAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
Non - U.S. Pension Plans | Effect of change in the measurement policy from annually to quarterly      
Amortization of unrecognized      
Total net (benefit) expense 0us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_DefinedBenefitPlansChangeInMeasurementAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
0us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_DefinedBenefitPlansChangeInMeasurementAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
0us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_DefinedBenefitPlansChangeInMeasurementAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_ForeignPensionPlansDefinedBenefitMember
U.S. Postretirement Benefit Plans      
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]      
Benefits earned during the year 0us-gaap_DefinedBenefitPlanServiceCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
0us-gaap_DefinedBenefitPlanServiceCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
0us-gaap_DefinedBenefitPlanServiceCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
Interest cost on benefit obligation 33us-gaap_DefinedBenefitPlanInterestCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
33us-gaap_DefinedBenefitPlanInterestCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
44us-gaap_DefinedBenefitPlanInterestCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
Expected return on plan assets (1)us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
(2)us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
(4)us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
Amortization of unrecognized      
Prior service (benefit) cost 0us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
(1)us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
(1)us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
Net actuarial loss 0us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
0us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
4us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
Curtailment loss 0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToCurtailments
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToCurtailments
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToCurtailments
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
Settlement (gain) loss 0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
0us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
Special termination benefits 0us-gaap_DefinedBenefitPlanOtherCosts
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
0us-gaap_DefinedBenefitPlanOtherCosts
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
0us-gaap_DefinedBenefitPlanOtherCosts
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
Total net (benefit) expense 32us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
30us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
43us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
U.S. Postretirement Benefit Plans | Before adjustment due to change in accounting policy      
Amortization of unrecognized      
Total net (benefit) expense 32us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_BeforeAdjustmentDueToChangeInAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
30us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_BeforeAdjustmentDueToChangeInAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
43us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
= c_BeforeAdjustmentDueToChangeInAccountingPolicyMember
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember
U.S. Postretirement Benefit Plans | Effect of change in the measurement policy from annually to quarterly      
Amortization of unrecognized      
Total net (benefit) expense 0us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
/ us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis
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Non-U.S. Postretirement Benefit Plans      
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]      
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Amortization of unrecognized      
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Non-U.S. Postretirement Benefit Plans | Before adjustment due to change in accounting policy      
Amortization of unrecognized      
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Non-U.S. Postretirement Benefit Plans | Effect of change in the measurement policy from annually to quarterly      
Amortization of unrecognized      
Total net (benefit) expense $ 0us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
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