Derivatives and Hedging Activities (Details Textuals) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Derivatives and Hedging Activities (Textuals) [Abstract]
Net reduction in interest expense on long term debt and other	$ (20)	$ 24	$ (19)	$ 105
Margin On Interest Rate Swap Not Netted	99		99		$ 146
Derivative [Line Items]
Notional amount of long-term debt	24,200		24,200		23,600
Cummulative fair value hedging adjustment of hedged item in fair value hedge	513		513		182
Other Expense [Member]
Derivative [Line Items]
Gain (Loss) in Changes of Fair Value of Derivatives not designated as hedges	(8)	(15)	26	(36)
Gain on embedded derivatives	(5)	1	(11)	(1)
Fair Value Hedges [Member]
Derivative [Line Items]
Notional amount of long-term debt	24,800		24,800		$ 23,800
Net Investment Hedges [Member]
Derivative [Line Items]
Effective portion of gain (loss) on hedges	(22)	(184)	136	(515)
Net Investment Hedges [Member] | Other Expense [Member]
Derivative [Line Items]
Amount reclassified from AOCI into income	0	(18)	1	(18)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ 0	$ (18)	$ 1	$ (18)