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	7
Retirement of common stock/cancellation of shares	(78)	(72)
Net income (loss)		329		329
Common stock dividends declared (2015 - $0.20; 2014 - $0.16)		(42)
Other comprehensive income (loss), net of tax			890	890
Balance as of end-of-period at Mar. 31, 2014	6,805	5,228	2,453	14,486
Balance as of beginning-of-year at Dec. 31, 2014	6,622	6,022	3,096	15,740
Stock compensation/issued for benefit plans	27
Retirement of common stock/cancellation of shares	(156)	(194)
Net income (loss)		300		300
Common stock dividends declared (2015 - $0.20; 2014 - $0.16)		(51)
Other comprehensive income (loss), net of tax			557	557
Balance as of end-of-period at Mar. 31, 2015	$ 6,493	$ 6,077	$ 3,653	$ 16,223