Consolidated Comprehensive Income Statement (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net gain (loss) arising during the period	$ (514)	$ 287	$ 312	$ (24)	$ (696)