Derivatives and Hedging Activities (Details Textuals) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Derivatives and Hedging Activities (Textuals) [Abstract]
Net reduction in interest expense on long term debt and other	$ 14	$ 44
Margin On Interest Rate Swap Not Netted	125		$ 146
Derivative [Line Items]
Notional amount of long-term debt	22,900		23,600
Gross amount of hedged item	23,400		23,800
Cummulative fair value hedging adjustment of hedged item in fair value hedge	(392)		$ (182)
Effective portion of gain (loss) on hedges	(162)	(229)
Other Expense [Member]
Derivative [Line Items]
Gain (Loss) in Changes of Fair Value of Derivatives not designated as hedges	(21)	(17)
Gain on embedded derivatives	(2)	1
Net Investment Hedges [Member] | Other Expense [Member]
Derivative [Line Items]
Amount reclassified from AOCI into income	1	0
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ 1	$ 0