Postretirement Benefit Plans (Changes in Level 3 Investments) (Details) (Pension Benefit Plan [Member], Changes In Level 3 Investments [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan, Transfers Between Measurement Levels
Fair value of plan assets, Balance at January 1,	$ 12,003	$ 11,985
Net realized gains (losses)	540	180
Net unrealized gains (losses)	1,118	798
Purchases, issuances, and settlements	(2,172)	(912)
Transfers in and/or out of Level 1	(244)	(48)
Fair value of plan assets, Balance at December 31,	11,245	12,003
Fixed Income And Cash Investment Funds [Member]
Defined Benefit Plan, Transfers Between Measurement Levels
Fair value of plan assets, Balance at January 1,	50	62
Net realized gains (losses)	(7)	0
Net unrealized gains (losses)	0	9
Purchases, issuances, and settlements	(43)	(21)
Transfers in and/or out of Level 1	0	0
Fair value of plan assets, Balance at December 31,	0	50
Domestic Corporate Debt Securities [Member]
Defined Benefit Plan, Transfers Between Measurement Levels
Fair value of plan assets, Balance at January 1,		3
Net realized gains (losses)		(1)
Net unrealized gains (losses)		0
Purchases, issuances, and settlements		(2)
Transfers in and/or out of Level 1		0
Residential Mortgage Backed Securities [Member]
Defined Benefit Plan, Transfers Between Measurement Levels
Fair value of plan assets, Balance at January 1,	3	5
Net realized gains (losses)	0	(2)
Net unrealized gains (losses)	0	0
Purchases, issuances, and settlements	0	0
Transfers in and/or out of Level 1	(3)	0
Fair value of plan assets, Balance at December 31,	0	3
Other Debt Obligations [Member]
Defined Benefit Plan, Transfers Between Measurement Levels
Fair value of plan assets, Balance at January 1,	22	146
Net realized gains (losses)	0	(2)
Net unrealized gains (losses)	0	0
Purchases, issuances, and settlements	(22)	(122)
Transfers in and/or out of Level 1	0	0
Fair value of plan assets, Balance at December 31,	0	22
Private Equities [Member]
Defined Benefit Plan, Transfers Between Measurement Levels
Fair value of plan assets, Balance at January 1,	6,878	6,786
Net realized gains (losses)	525	133
Net unrealized gains (losses)	588	438
Purchases, issuances, and settlements	(1,675)	(479)
Transfers in and/or out of Level 1	(47)	0
Fair value of plan assets, Balance at December 31,	6,269	6,878
Real Estate [Member]
Defined Benefit Plan, Transfers Between Measurement Levels
Fair value of plan assets, Balance at January 1,	3,356	3,274
Net realized gains (losses)	23	20
Net unrealized gains (losses)	330	279
Purchases, issuances, and settlements	(355)	(217)
Transfers in and/or out of Level 1	0	0
Fair value of plan assets, Balance at December 31,	3,354	3,356
Other Investments [Member]
Defined Benefit Plan, Transfers Between Measurement Levels
Fair value of plan assets, Balance at January 1,	1,694	1,709
Net realized gains (losses)	(1)	32
Net unrealized gains (losses)	200	72
Purchases, issuances, and settlements	(77)	(71)
Transfers in and/or out of Level 1	(194)	(48)
Fair value of plan assets, Balance at December 31,	$ 1,622	$ 1,694