Changes in Accumulated Other Comprehensive Income (Loss) Textuals (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Accumulated Other Comprehensive Loss Income (Textuals) [Abstract]
Amount of gain loss reclassified from accumulated other comprehensive income to income	$ 0	$ 0

Net gain (loss) reclassified from accumulated other comprehensive income into income.

No definition available.

Name:	aexc_NetGainLossReclassifiedFromAccumulatedOtherComprehensiveIncomeToIncome
Namespace Prefix:	aexc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration