Significant Accounting Policies (Policies)	6 Months Ended
Jun. 30, 2018
Summary Of Significant Accounting Policies [Abstract]
Basis of Presentation	The preparation of Consolidated Financial Statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses. These accounting estimates reflect the best judgment of management, but actual results could differ.
Derivatives And Hedging Activities Policy [Abstract]
Derivatives	Credco uses derivative financial instruments (derivatives) to manage exposures to various market risks. These instruments derive their value from an underlying variable or multiple variables, including interest rates and foreign exchange rates, and are carried at fair value on the Consolidated Balance Sheets. The changes in the fair value of derivatives that are not designated as hedges are intended to offset the related foreign exchange gains or losses of the underlying foreign currency exposures
Variable Interest Entity [Abstract]
Variable Interest Entity	Credco established a Variable Interest Entity, American Express Canada Credit Corporation (AECCC), primarily to issue notes in Canada under a medium-term note program and lend the proceeds to affiliates. The notes issued under the medium-term note program are fully guaranteed by Credco. Credco is considered the primary beneficiary of the entity and owns all of the outstanding voting interests and, therefore, consolidates the entity.

Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2018

Summary Of Significant Accounting Policies [Abstract]

The preparation of Consolidated Financial Statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses. These accounting estimates reflect the best judgment of management, but actual results could differ.

Derivatives And Hedging Activities Policy [Abstract]

Derivatives

Credco uses derivative financial instruments (derivatives) to manage exposures to various market risks. These instruments derive their value from an underlying variable or multiple variables, including interest rates and foreign exchange rates, and are carried at fair value on the Consolidated Balance Sheets.

The changes in the fair value of derivatives that are not designated as hedges are intended to offset the related foreign exchange gains or losses of the underlying foreign currency exposures

Variable Interest Entity [Abstract]

Variable Interest Entity

Credco established a Variable Interest Entity, American Express Canada Credit Corporation (AECCC), primarily to issue notes in Canada under a medium-term note program and lend the proceeds to affiliates. The notes issued under the medium-term note program are fully guaranteed by Credco. Credco is considered the primary beneficiary of the entity and owns all of the outstanding voting interests and, therefore, consolidates the entity.