Contractual interest rate for funds borrowed, under the debt agreement.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

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-Name Accounting Standards Codification

-Topic 210

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

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Interest expense incurred during the reporting period on junior subordinated debentures. Includes amortization of expenses incurred in the issuance of subordinated notes and debentures.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 8

-Article 9

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

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-Name Accounting Standards Codification

-Topic 942

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-Section S99

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Junior Subordinated Debt Securities (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Interest Expense, Junior Subordinated Debentures	$ 258	$ 258	$ 258
Senior Note MLINC $1B maturing in June 2035 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.70%
Debt Instrument, Maturity Date	Jun. 30, 2035
Junior Subordinated Debt Instrument One [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	10.75%
Debt Instrument, Maturity Date	Aug. 01, 2069
Junior Subordinated Debt Instrument Four [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.40%
Debt Instrument, Maturity Date	Dec. 15, 2066
Junior Subordinated Debt Instrument Three [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.875%
Debt Instrument, Maturity Date	Dec. 15, 2067
Junior Subordinated Debt Instrument Two [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	9.25%
Debt Instrument, Maturity Date	Apr. 08, 2068