Equity AOCI (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012	Jun. 30, 2013		Jun. 30, 2012
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 1,038			$ 384
Other comprehensive income before reclassifications	233			880
Amounts reclassified from other comprehensive income	(67)			(60)
Total other comprehensive income (loss)	166		328	820		690
Ending balance	1,204			1,204
Available-for-Sale Securities [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	1,582	[1]		934	[1]
Other comprehensive income before reclassifications	88	[1]		735	[1]
Amounts reclassified from other comprehensive income	(71)	[1]		(70)	[1]
Total other comprehensive income (loss)	17	[1]		665	[1]
Ending balance	1,599	[1]		1,599	[1]
Accumulated Other Comprehensive Income (Loss), Other [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(544)	[2]		(550)	[2]
Other comprehensive income before reclassifications	145	[2]		145	[2]
Amounts reclassified from other comprehensive income	4	[2]		10	[2]
Total other comprehensive income (loss)	149	[2]		155	[2]
Ending balance	$ (395)	[2]		$ (395)	[2]

[1] ) The amounts reclassified from AOCI represent the gain or loss recognized in earnings due to a sale of an available-for-sale security or the recognition of a net impairment recognized in earning

[2] ) Primarily represents activity from our defined benefit pension plan