Derivative Instruments And Hedging Activities Derivative Instruments and Hedging Activities Gain/Loss in Income (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Types of Items Hedged by Interest Rate Derivatives	$ 5	$ 0
Increase (Decrease) in Fair Value of Hedged Item in Interest Rate Fair Value Hedge	(5)	0
Derivative, Gain (Loss) on Derivative, Net	0	0
Long-term Debt [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Liability, Fair Value Hedge	(505)	0
Hedged Liability, Fair Value Hedge, Cumulative Increase (Decrease)	$ (5)	$ 0

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
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Amount of increase in the fair value of derivatives recognized in the income statement.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
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+ References

No definition available.

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Amount of liability hedged in fair value hedging relationship.

+ References

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-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
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Amount of cumulative increase (decrease) in fair value of hedged liability in fair value hedge, attributable to hedged risk.

+ References

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Amount of unrealized gain (loss) included in earnings related to the fair value of the hedged item in an interest rate fair value hedge, offset by the gain (loss) on the hedging instrument to the extent that the fair value hedge is determined to be effective.

+ References

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