Guarantor (Statement of Financial Position - Paranthetical) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Guarantee Obligations [Line Items]
Cash and equivalents	$ 75,075	$ 70,483
Investment in subsidiaries
Guarantee Obligations [Line Items]
Cash and equivalents	37,900	40,100
Discontinued Operations [Member] \| Investment in subsidiaries
Guarantee Obligations [Line Items]
Net assets	$ 33,600	$ 40,000

Amount of net assets (liabilities).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 225
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-09.6,7)
-URI http://asc.fasb.org/extlink&oid=6488393&loc=d3e606914-122999

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=35686370&loc=SL35686385-199418

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section S99
-Paragraph 2
-Subparagraph (SX 210.6-05.4)
-URI http://asc.fasb.org/extlink&oid=6488278&loc=d3e604008-122996

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 09
-Paragraph 19
-Article 6

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