Pension Plans, Retirement Benefits and Savings Plans (details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Plans [Member]
Change in projected benefit obligation [Roll Forward]
Benefit obligation, balance, beginning of year	$ 3,117	$ 3,261
Benefits earned	110	118	113
Interest cost on benefit obligation	150	132	138
Actuarial loss (gain)	457	(262)
Benefits paid	(198)	(149)
Plan amendments	(8)
Curtailment	(3)
Settlement	(6)
Foreign currency exchange rate change, change in projected benefit obligation	(7)	2
Acquisition		15
Benefit obligation, balance, end of year	3,612	3,117	3,261
Change in plan assets [Roll Forward]
Fair value of plan assets, balance, beginning of year	3,203	2,859
Actual return on plan assets	159	465
Company contributions	207	6
Benefits paid	(198)	(149)
Foreign currency exchange rate change, change in plan assets	(8)	2
Settlement	(6)
Acquisition		20
Fair value of plan assets, balance, end of year	3,357	3,203	2,859
Funded status of plan at end of year	(255)	86
Amounts recognized in the consolidated balance sheet consist of:
Accrued over-funded benefit plan assets	6	186
Accrued under-funded benefit plan liabilities	(261)	(100)
Total amount recognized in the consolidated balance sheet	(255)	86
Amounts recognized in accumulated other comprehensive income consist of:
Net actuarial loss (gain)	1,185	738
Prior service benefit	(8)
Total amount recognized in accumulated other comprehensive income	1,177	738
Qualified Domestic Pension Plan [Member]
Change in projected benefit obligation [Roll Forward]
Benefit obligation, balance, beginning of year	2,908	3,055
Benefits earned	104	112
Interest cost on benefit obligation	140	124
Actuarial loss (gain)	428	(243)
Benefits paid	(187)	(140)
Plan amendments	(8)
Benefit obligation, balance, end of year	3,385	2,908	3,055
Change in plan assets [Roll Forward]
Fair value of plan assets, balance, beginning of year	3,074	2,761
Actual return on plan assets	148	453
Company contributions	200	0	217
Benefits paid	(187)	(140)
Fair value of plan assets, balance, end of year	3,235	3,074	2,761
Funded status of plan at end of year	(150)	166
Amounts recognized in the consolidated balance sheet consist of:
Accrued over-funded benefit plan assets		176
Accrued under-funded benefit plan liabilities	(150)	(10)
Total amount recognized in the consolidated balance sheet	(150)	166
Amounts recognized in accumulated other comprehensive income consist of:
Net actuarial loss (gain)	1,132	704
Prior service benefit	(8)
Total amount recognized in accumulated other comprehensive income	1,124	704
Nonqualified and Foreign Pension Plans [Member]
Change in projected benefit obligation [Roll Forward]
Benefit obligation, balance, beginning of year	209	206
Benefits earned	6	6
Interest cost on benefit obligation	10	8
Actuarial loss (gain)	29	(19)
Benefits paid	(11)	(9)
Curtailment	(3)
Settlement	(6)
Foreign currency exchange rate change, change in projected benefit obligation	(7)	2
Acquisition		15
Benefit obligation, balance, end of year	227	209
Change in plan assets [Roll Forward]
Fair value of plan assets, balance, beginning of year	129	98
Actual return on plan assets	11	12
Company contributions	7	6
Benefits paid	(11)	(9)
Foreign currency exchange rate change, change in plan assets	(8)	2
Settlement	(6)
Acquisition		20
Fair value of plan assets, balance, end of year	122	129
Funded status of plan at end of year	(105)	(80)
Amounts recognized in the consolidated balance sheet consist of:
Accrued over-funded benefit plan assets	6	10
Accrued under-funded benefit plan liabilities	(111)	(90)
Total amount recognized in the consolidated balance sheet	(105)	(80)
Amounts recognized in accumulated other comprehensive income consist of:
Net actuarial loss (gain)	53	34
Total amount recognized in accumulated other comprehensive income	53	34
Postretirement Benefit Plans [Member]
Change in projected benefit obligation [Roll Forward]
Benefit obligation, balance, beginning of year	211	222
Interest cost on benefit obligation	10	9	12
Actuarial loss (gain)	51	(25)
Benefits paid	(15)	(14)
Foreign currency exchange rate change, change in projected benefit obligation	(2)
Acquisition		19
Benefit obligation, balance, end of year	255	211	222
Change in plan assets [Roll Forward]
Fair value of plan assets, balance, beginning of year	17	18
Company contributions	14	13
Benefits paid	(15)	(14)
Fair value of plan assets, balance, end of year	16	17	18
Funded status of plan at end of year	(239)	(194)
Amounts recognized in the consolidated balance sheet consist of:
Accrued under-funded benefit plan liabilities	(239)	(194)
Total amount recognized in the consolidated balance sheet	(239)	(194)
Amounts recognized in accumulated other comprehensive income consist of:
Net actuarial loss (gain)	9	(44)
Prior service benefit	(26)	(28)
Total amount recognized in accumulated other comprehensive income	$ (17)	$ (72)