Shareholders' Equity (Accumulated Other Comprehensive Income by Component) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended		1 Months Ended		1 Months Ended		1 Months Ended		1 Months Ended		1 Months Ended		1 Months Ended
	Mar. 31, 2013	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges	Dec. 31, 2012 Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges	Mar. 31, 2013 Accumulated Net Unrealized Investment Gain (Loss)	Dec. 31, 2012 Accumulated Net Unrealized Investment Gain (Loss)	Mar. 31, 2013 Accumulated Net Unrealized Gain (Loss) on Net Investment Hedging	Dec. 31, 2012 Accumulated Net Unrealized Gain (Loss) on Net Investment Hedging	Mar. 31, 2013 Accumulated Other-than-Temporary Impairment	Dec. 31, 2012 Accumulated Other-than-Temporary Impairment	Mar. 31, 2013 Accumulated Defined Benefit Plans Adjustment	Dec. 31, 2012 Accumulated Defined Benefit Plans Adjustment	Mar. 31, 2013 Accumulated Translation Adjustment	Dec. 31, 2012 Accumulated Translation Adjustment
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]
AOCI net of tax, beginning balance		$ 360			$ 69		$ 519		$ (14)		$ (65)		$ (283)		$ 134
Other comprehensive income (loss) before reclassifications	(114)			63		69		0		4		(2)		(248)
Amounts reclassified out of AOCI	5			1		(3)		0		2		5		0
Other comprehensive income (loss)	(109)	(109)	360	64		66		0		6		3		(248)
AOCI net of tax, ending balance	$ 251	$ 251		$ 133	$ 69	$ 585	$ 519	$ (14)	$ (14)	$ (59)	$ (65)	$ (280)	$ (283)	$ (114)	$ 134