Derivatives and Hedging Activities Textuals (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivatives And Hedging Activities Textuals [Abstract]
Net (increase) reduction in interest expense on long term debt.	$ (75)	$ 53	$ 126
Derivative [Line Items]
Notional amount of long-term debt	13,500	16,000
Loss (gain) on net investment hedges	(127)	174	(80)
Margin on interest rate swap not netted	55	115
Gain in Changes of Fair Value of Derivatives not designated as hedges	59	21	$ 1
Cumulative Fair Value hedging adjustments of hedged item in fair value hedge	184	155
Notional Amount of Foreign Currency Derivatives	2,900	3,000
Fair Value Hedging [Member]
Derivative [Line Items]
Notional amount of long-term debt	$ 13,800	$ 16,200