Derivative Instruments And Hedging Activities (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Forward Contract Indexed to Issuer's Equity [Line Items]
Cash Collateral Placed with Counterparties	$ 72	$ 221
Securities Collateral Placed with Counterparties	111	15
Cash collateral received from counterparties	129	71
Non-cash collateral received	8	$ 15
Other Assets [Member]
Forward Contract Indexed to Issuer's Equity [Line Items]
Prepaid Expense	$ 47

Carrying amount as of the balance sheet date of expenditures made in advance of when the economic benefit of the cost will be realized, and which will be expensed in future periods with the passage of time or when a triggering event occurs.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.10)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.10)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Name:	us-gaap_PrepaidExpenseCurrentAndNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant