Consolidated Statements Of Stockholders' Equity - USD ($) $ in Millions	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance as of beginning-of-year at Dec. 31, 2013	$ 6,876	$ 5,013	$ 1,563
Stock compensation/issued for benefit plans	20
Retirement of common stock/cancellation of shares	(157)	(143)
Net income (loss)		727		$ 727
Common stock dividends declared (2015 - $0.40; 2014 - $0.32)		(84)
Other comprehensive income (loss), net of tax			1,636	1,636
Balance as of end-of-period at Jun. 30, 2014	6,739	5,513	3,199	15,451
Balance as of beginning-of-year at Dec. 31, 2014	6,622	6,022	3,096	15,740
Stock compensation/issued for benefit plans	68
Retirement of common stock/cancellation of shares	(221)	(279)
Net income (loss)		644		644
Common stock dividends declared (2015 - $0.40; 2014 - $0.32)		(101)
Other comprehensive income (loss), net of tax			(1,152)	(1,152)
Balance as of end-of-period at Jun. 30, 2015	$ 6,469	$ 6,286	$ 1,944	$ 14,699