Condensed Consolidated Statements of Changes in Common Shareholders' Equity (USD $) In Millions, except Share data	Common Shares [Member]	Paid-in-Surplus [Member]	Retained Earnings [Member]	Treasury Stock [Member]	AOCI [Member]		Total
Shareholders' equity, beginning balance at Dec. 31, 2013	$ 2,774	$ 4,210	$ 23,901	$ (8,910)	$ (750)	[1]	$ 21,225
Common shares, beginning balance at Dec. 31, 2013	1,109,700,000			(197,700,000)
Net income			1,088				1,088
Other comp. income/(loss)					16	[1]	16	[2]
Conversion, stock option exercises, forfeitures, and other	1	23		16			40
Conversion, stock option exercises, forfeitures, and other (shares)	400,000			1,200,000
Share repurchases (Note 18)				(683)			(683)
Share repurchases (Note 18) (shares)				(7,600,000)			(7,640,000)
Cash dividends declared			(414)				(414)
Shareholders' equity, ending balance at Mar. 31, 2014	2,775	4,233	24,575	(9,577)	(734)	[1]	21,272
Common shares, ending balance at Mar. 31, 2014	1,110,100,000			(204,100,000)
Shareholders' equity, beginning balance at Dec. 31, 2014	2,775	4,321	27,367	(12,064)	(1,210)	[1]	21,189
Common shares, beginning balance at Dec. 31, 2014	1,110,100,000			(226,700,000)			883,366,476
Net income			1,151				1,151
Other comp. income/(loss)					(8)	[1]	(8)	[2]
Conversion, stock option exercises, forfeitures, and other	1	30		(15)			16
Conversion, stock option exercises, forfeitures, and other (shares)	400,000			500,000
Share repurchases (Note 18)				(807)			(807)
Share repurchases (Note 18) (shares)				(6,900,000)			(6,881,455)
Cash dividends declared			(484)				(484)
Shareholders' equity, ending balance at Mar. 31, 2015	$ 2,776	$ 4,351	$ 28,034	$ (12,886)	$ (1,218)	[1]	$ 21,057
Common shares, ending balance at Mar. 31, 2015	1,110,500,000			(233,100,000)			877,373,800

[1] AOCI = Accumulated Other Comprehensive Income/(Loss) (Note 10)

[2] Net of deferred taxes of $(3) million and $5 million during the three months ended March 31, 2015, and 2014, respectively.