Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance , beginning of period	$ 6,202	$ 11,397
OCI before reclassifications	(1,038)	(6,158)
Amounts reclassified from AOCI	(64)	(139)
Balance, end of period	5,100	5,100
Unrealized Investment Gains (Losses), Net of Related Offsets [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance , beginning of period	9,709	13,590
OCI before reclassifications	(1,060)	(4,635)
Amounts reclassified from AOCI	55	(251)
Balance, end of period	8,704	8,704
Unrealized Gains (Losses) on Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance , beginning of period	734	829
OCI before reclassifications	(184)	(439)
Amounts reclassified from AOCI	(154)	6
Balance, end of period	396	396
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance , beginning of period	(1,825)	(533)
OCI before reclassifications	207	(1,085)
Amounts reclassified from AOCI	0	0
Balance, end of period	(1,618)	(1,618)
Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance , beginning of period	(2,416)	(2,489)
OCI before reclassifications	(1)	1
Amounts reclassified from AOCI	35	106
Balance, end of period	$ (2,382)	$ (2,382)