Derivatives and Hedging Activities Textuals (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Derivatives And Hedging Activities Textuals [Abstract]
Net increase in interest expense on long term debt.	$ 28	$ 19	$ 60	$ 23
Derivative [Line Items]
Notional amount of long-term debt	11,000		11,000		$ 13,500
Gain (loss) on net investment hedges	36	105	(21)	62
Amounts reclassified from AOCI into income	0	0	0	0
Margin on interest rate swap not netted	48		48		55
Gain in Changes of Fair Value of Derivatives not designated as hedges	26	$ 15	49	$ 30
Cumulative Fair Value hedging adjustments of hedged item in fair value hedge	29		29		184
Notional Amount of Foreign Currency Derivatives	2,900		2,900		2,900
Fair Value Hedging [Member]
Derivative [Line Items]
Notional amount of long-term debt	$ 11,000		$ 11,000		$ 13,800