Consolidated Statements Of Comprehensive Income (Parenthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net Unrealized gains (losses) on available-for-sale securities, tax	$ 0	$ 0	$ 0
Realized gains on available-for-sale securities reclassified to earnings, tax	1	0	0
Net unrealized holding losses arising during period,tax	1	2	19
Cash flow hedges reclassified to earnings, tax	(9)	(23)	(59)
Pension and post retirement benefits, tax	1	19	3
Pension and post retirement benefits reclassified to earnings, tax	$ (6)	$ (3)	$ (2)