XML 99 R84.htm IDEA: XBRL DOCUMENT v3.10.0.1
Derivative financial instruments (Narrative) (Details) - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]    
Derivative cash collateral, obligation to return cash $ 5,500,000 $ 3,700,000
Derivative cash collateral, advanced to counterparties 0 $ 0
Cash flow hedge gain (loss) to be reclassified within 12 months $ 11,000,000